VAERS has it's flaws, as noted by @Liewtrah381, but it's not useless. The data may be better when reported by a healthcare professional, but VAERS allows self-reporting, or third-party reporting, which makes for noisier data that could only indicate correlation, not causation...but if trends emerge in the data, it does get looked at more closely to see if there might be a causal link.
There was a VAERS entry made early on, as vaccination started becoming highly political, by someone who claimed the Covid vaccine turned him into the Incredible Hulk.