Happy New Year Laophil and all other collectors, of primates or any other issues!
To try and answer your question, I don't think it is to prevent counterfeiting - but with some of the very detailed stamps you can not always get a good scan so photographing is better or with new issues, go to the official website and see if you can get a screen shot.
Most of my Malaysian items come across in better colours so let me try to show some:

I had to adjust this image to conform with the size requirements - still, not bad
Special cover, no 00625, with MS 740, M: 752D
Mamalia Yang Dilindungi di Malaysia, "Protected Animals of Malaysia"
RM2
Orang-utan (Pongo pygmaeus)
Stamp Exhibition, Philatelic Society of Kota Kinabalu, 2001
Cancels:
1. Philatelic Society of Kota Kinabalu, 29th Sept-01st Oct 2001, Stampex;
2. Two triangular cancels:
• Map of Kota Kinabalu, 29 Sept – Okt 2001, Pos Malaysia, Kota Kinabalu, Stampex;
• 30Sept 2001, Pos Malaysia, Kota Kinabalu
Cachet: Colour illustration of orang-utan stamp, North Borneo, 296, M: 217

This FDC has the MS of a series "Nocturnal animals" - the eyes reflect light in the dark!
MS of 2
"Nocturnal Animals, Haiwan Nokturnal"
RM 2, Tarsier (Tarsius bancatus)
RM 3, Slow loris (Nycticebus coucang)
In border: Loris and tarsier, heads
FDC with MS1478
Cancel: Mouse, Haiwan Nokturnal, 13 Mac 2008, Biro Filateli, Kuala Lumpur
Cachet: Colour illustration, night sky with moon backdrop for barn owl