How many buttons do you need on the steering wheel? Logitech G25 vs G27 vs G29

United States
United States
The G25 has only 2 buttons on the wheel. G27, 6 buttons. G29, 8 or more, I cannot tell from internet pictures.

The G25 and G27 came with a shifter with some extra buttons. So, it seems like they were trying to move buttons from the shifter to the wheel with the G29, is this correct?

Do people run into problems playing racing games on the older wheels due to a lack of buttons? The games I will be playing in the near future are Grid 2, F1 2015, Dirt Rally, Gran Turismo Sport. Do any of those wheels suffer in those games from a lack of buttons?

I might be able to get a G25 locally on Craigslist for only $45 vs around $200 for the others. I do have Drivehub, so PS4 compatibility is no problem.