When I learned to dive, dive computers were crude and expensive, so i did everything the manual way - dive plan in advance and no fancy kit (depth gauge, watch and check air supply status) & memorized "emergency" ascent best practice (if emergency not critical enough to let you do the stops, e.g. supply fail from one tank but using 2 tanks)
I used them later but only as an emergency backup in case of nitrogen narcosis (your concentration fails if affected by that so having a device warn you is a potential life saver in worst case scenario where dive buddy also impaired).
I'm sure if I had learned to dive later, when the tech was better & cheaper, I would have been a keen dive computer user.
Full disclosure I did BSAC (not PADI), no longer dive as life threatening chest infection irreversibly hammered my lung function some years ago to the point where diving was not worth it (could have gone the rebreather route to get a vaguely decent dive time with dismal lungs but cost & extra training & certification was a deal breaker as by then I dived infrequently, made sure I just did enough to keep my certifications "live" as had moved a long way from sea by then)