No, I don't think for a second that a belt will negate chronically bad form, and the use of a belt can be controversial to some. I wear a belt, but I'm not super invested in either side of the debate. One can certainly progress and get strong without one.
As far as actual data and research into wearing a belt for safety, there seems to be some mixed findings. Most of which is inconclusive with respect to primary injury prevention. One aspect that does seem to have a bit more sway is in secondary injury prevention - ie you already have a ****ed up back but you still want to lift without further injury. In this case, there may be an actual benefit to wearing a belt for your heavier reps/sets.
In my own experience, anecdotally of course, I've had a "slipped" disc, ie disc protrusion for a number of years. Got it long before I ever started lifting. For 2-3 years I was walking with a limp, wincing with pain every time I got up or down or in/out of the car. Shooting pain down the back of my left leg for years. It would come and go, and one time it went away for about 6 months.
I coincidentally started lifting then, and used some cheap ****** Golds belt. I progressed okay, but after a few months I lost my belt. A few weeks after that, my sciatic pains came back. Got it imaged, and the vertebrae in my lower back are all out of alignment (this was true before I started lifting). ****.
Took some time off, pain went away, came back slowly but with a good powerlifting belt. Been years now, and for the most part the pain hasn't been back. I've had one brief episode of pain that lasted for about 2 days, but nothing like the months or years that I'd had before. I put this down mainly to proper training and strengthening the supportive muscles in my lower back. And maybe a little to proper belt use. There is a 'right-ish' way to wear and use a belt.
I always do my warm-up and lighter weights without the belt. I will belt up for the last warm up set/rep before my work set. Wear the belt fairly tight, take a deep breath before your rep, push your abs hard into the belt and hold a strong Valsalva for the entire duration of the rep. I don't know came up with this exhale/eccentric inhale/concentric ******** - probably never lifted
"this heavy-ass weight".
Belt use also has a another benefit - you can lift more weight. Not only that, but some argue you can actually progress at a faster rate as the belt enables you to work harder as a whole. The belt doesn't technically help lift (in the sense that knee wraps do), but it just enables you to stay tighter and provide a more stable platform to lift.
But if you're having some mobility problems and chronic form issues, the belt is not going to help that. The belt isn't necessarily a solution to a correctable problem. Sort those out first.
