How the buttons that are always there cumbersome?

I personally don't like gestures. You have to remember and get used to them. Then suddenly in a major update they will change everything to new "cooler" gesture, re-learn and get used to it again. Year after year that happens.

Compare that to buttons. You can always see them, so no need to remember anything. Older people also able to use them.

Of course new shiny mobile os have mixed both together and now we are guinea pigs of modern UI.