Both leaf switches and microswitches were both used from the very beginning. Leaf switch buttons WERE the most common, but even many early-mid 70s games had microswitches.
The most common early microswitch using games tended to either have 2-way microswitch joysticks, or to have leaf style buttons that instead hit microswitches with actuator arms. Microswitch based start buttons were also extremely common. In general microswitch based stuff was common in games from Atari, Nintendo, Sega, ATW, Midway, and others.
If you don't believe me, then come into my gameroom and let me show you stuff from 1976, 1978, and 1980 (3 different titles from that year) that all have factory microswitch controls installed.
Also, I am an ex owner of a Nintendo Vs. cabinet, and my neighbor currently has a Playchoice. Those Nintendo 8-way joys are terrible. They were designed to be compact and to be long lasting, not to have a good feel. I would pick almost ANY other stick over one of them.