Against a good Fox, Falco, Wolf, Lucario, and maybe Lucas, rolling is one of the better options you have to get out of their shield pressure. That said, most low to mid level players will probably not be good enough at shield pressure to warrant you rolling, so it depends on your opponents skill as well.
Aside from that, rolling is situational, but not useless. When someone aerials -> to instant jab, the jab/grab mix ups are dangerous and rolling is not an out of the question response (though not the go-to response either). You might also use it when someone commits to extended forward momentum, like when Ganon uses side b. If you react to the side B and don't have other better punish options (like dash away, dash back after the move is done, and hit him), then rolling can soft punish him by allowing you to steal center stage.
Rolling is out classed by other options more often by not, and a lot of low to mid level players overuse rolling by a lot, but it's an overstatement to say that you shouldn't roll.
Edit: That said, if you're just learning to roll less, putting the restriction of not rolling in matches is not a bad idea for the purpose of learning. You can always add rolling back into your game once you understand/get used to your other options (mostly dashing away, and sometimes wavedashing away).