Weak absorbance in NIR region is beneficial.

"The primary advantage of the NIR region is that absorbances are lower than in neighbouring regions and generally obey the Beer/Lambert law, i.e., absorbance increases linearly with concentration. This is because NIR absorptions are generally 10-100 times weaker in intensity than the fundamental mid-IR absorption bands. The weakness of the absorptions is a benefit, providing direct analysis of samples without dilution or the requirement of short optical pathlengths or dispersion in non-absorbing matrices used in traditional sampling techniques in UV/Vis and mid-IR spectroscopies."

(http://www.pdkprojects.com/aboutnirs.html#calibration)

High resolution is not necessary for NIRS (Spectral resolution less than 10 nm is sufficient)

"Averaging over wavelengths is used to reduce the number of
wavelengths or to smooth the spectrum. Modern spectrophotometers
typically have an optical resolution beyond 10 nm,
whereas a 10 nm resolution is often sufficient for most applications.
Also, most spectrophotometers provide a better spectral
resolution (often 1–2 nm) than the actual optical resolution;
while this certainly increases statistical processing time it does
not improve the information content of the spectra. Further,
below 1100 nm the bandwidth of absorption peaks is typically
larger than 40 nm (Greensill et al., 2001, and references therein).
Nicola¨ı et al. (2006a) artificially inflated NIR reflectance spectra
of apple with a 2 nm resolution tenfold to 0.2 nm resolution; arti-
ficial reflectance values between two neighbouring wavelengths
in the original spectra were obtained by linear interpolation,
and Gaussian noise was added. The accuracy of the corresponding
PLS model was very low but increased by removing
redundant high resolution information by means ofwavelet compression.
The best results were obtained with compression ratios
of 20–30, loosely corresponding to a wavelength resolution of
about 5 nm."

(Nondestructive measurement of fruit and vegetable quality
by means of NIR spectroscopy: A review
Bart M. Nicola¨ı, Katrien Beullensa, Els Bobelyna, Ann Peirs ,
Wouter Saeys , Karen I. Theron , Jeroen Lammertyna
Postharvest Biology and Technology 46 (2007) 99–118)

"Resolution is one of the measurement parameters involved in obtaining spectra with FTIR.

The resolution can be set to values such as 16 cm^-1, 8 cm^-1, 4 cm^-1, or 2 cm^-1. It indicates the degree of fineness of the data obtained by measurement (i.e., the minimum peak interval that can be distinguished). For example, if 4 cm^-1 is selected, spectra will be obtained at intervals of approximately 2 cm^-1. To obtain sharper spectra (i.e., spectra with a higher resolution), a value such as 2 cm^-1 or 1 cm^-1 is set.
In fact, although this works for gaseous samples, there are cases with solid and liquid samples where the resolution of the data obtained does not improve even if a higher resolution is set. This is because the molecules of the solid or liquid are influenced by other molecules around them, causing the actual peaks to broaden.
Also, if the resolution is increased, a smaller aperture is selected in the way described later, and the intensity of the light entering the detector is reduced, increasing the relative amount of noise in the spectra. Therefore, it is undesirable for the resolution to be increased more than necessary.

For this reason, the resolution is usually set to approximately 4 cm^-1 for solid and liquid samples, and to approximately 1 cm^-1 or 0.5 cm^-1 for gaseous samples. On some occasions, a low resolution is set for gaseous samples if the purpose is quantification."
(http://www.shimadzu.com/an/ftir/support/tips/letter8/tech.html)

Disadvantage of NIR spectroscopy

"Like other techniques, NIR spectroscopy has also some drawbacks. The low sensitivity of this technique restricts the determination of the active principles with less than 0.01% (w/w). NIR spectroscopy is an indirect method which requires a reference method, Chemometric techniques - statistical and mathematical procedures - to extract, and interpret spectral information acquired from the sample NIR spectra"

(FT-NIR spectroscopy and Laser Diffraction particle sizing of APIs in Pharmaceutical formulations
Joana Lucia Carrilho Figuriredo, Mestrado Integrado em Engenharia Quimica, Setembro de 2008)
(Celio Pasquini (2003) Near Infrared Spectroscopy: Fundamentals, Practical Aspects and Analytical Applications: J. Braz. Chem. Soc.; Vol. 14 No. 2)

The reason NIR has an advantage over IR is that NIR has lower absorbance coefficients

"The reason NIR has an advantage over IR is that NIR has lower absorbance coefficients. Due to this, the optimum path length without dilution in the IR is in micrometers, where as long NIR is in millimeters and short NIR is in centimeters. This means that with NIR it is possible to measure representative sample portions with simple or no sample preparation. It is this lack of sample preparation makes this method preferred for analysis of agricultural and food materials."

(Near-Infrared Spectroscopy for Analysis of Agricultural Material Eric C. Newgard)