Is it? I’ve seen devs bring complicated code to the frontend when a required attribute on the tag would have done the job just as well. Preventing user mistakes is not the same as ensuring correct input.

We've all seen bad implementations of any given thing I'd imagine. Ever submit a form that triggers a full page refresh after about 8 seconds of hanging, only to lose half the data and reveal some arcane requirement to you that wasn't stated up front? Of course this isn't the proper way to do it, but it happens.