The system will operate as expected so long as the specifications relating to distance is followed. Thermal cameras are truly excellent solutions to see in pitch black.
Whether it’s intended for stealth vs having the ability to see a object not normally visible either in colour / IR.
It should be noted these thermal cameras come in higher quality (tolerance) vs the standard ones. This is especially important in extreme temperature environments like desert / arctic.
The use of various filters to identify different coloured objects only goes so far. Along with understanding the limitations when something is hidden behind foliage or heat reflecting / heat absorbing material.
Regardless of the above in a normal environment thermal cameras offer that extra insight and visibility not available from standard security cameras.
Now, if you want to get real serious invest in radar or integrated radar PTZ.