Far be it from me to question you guys given my
very limited experience but (there had to be a "but" didn't there...
) while I agree with taking responsibility for yourself, people do get complacent and can make mistakes.
So I think the buddy check is a good discipline as I don't want my buddy to spot something I've missed so it makes me more careful. It also makes your buddy concentrate (hopefully) as they do take some responsibility for you. And finally, it hopefully catches mistakes anyone might make...
I was diving in Sharm recently and on one dive the buddy checks were cursory to non-existent. We were getting ready to jump when I noticed one diver, (not my buddy
) who was (apparently) completing his 100th dive, had not attached his cylinder correctly and it was hanging on by not much more than a unfastened strap.
Bottom line, why wouldn't you do the check and take the 60 seconds to do it properly?