Analog Stick Buttons - Nessecary?

I'm just going over my pad config through ePSXe here and I've just sat wondering if there were actually any games for the PS that used the so called L3 and R3 buttons that you got from pressing down the analog sticks.

I know they're now pretty much essential in PS2 games, but I can't for the life of me think about any possible PS1 titles that actually used the buttons (if the actual button feature was even within the technology at the time).

Can anyone help me out on this because if it turns out that L3 and R3 weren't actually part of the PS1 controllers I'd like to bind Start and Select to my analog stick buttons.