So you want to have to press a button 20 times to put your microwave on for 10 minutes? What do you have against keypads?
Either they're for quickly reheating small amounts of leftovers or maybe boiling a cup of water for tea, and you have no idea for how long, in which +30 is all you need. You never do more than 2 minutes at a time. You'd never put something in for 10 minutes.
The other way is the microwave as a kitchen tool, where you do things like put in a large frozen family-size something (soup, veggies, etc.) and reheat it on 20% power for 20 minutes.
The 2-button microwave is awesome for the former group. It's useless for the latter group.