The main point is "legitimate source for what?". A reporting system like VAERS errs widely on the side of overreporting and explicitly doesn't require any causality, so that its data can be mined for surprising patterns to investigate that might uncover a causal link we didn't know about.
Any "There's X VAERS reports of the vaccine causing Y" claims thus heavily misuse the data source, because that's not what it is capturing.
There is spurious data in VAERS, but the CDC has methods in place to filter those out in their research into adverse cardiac effects. Their numbers are in no way exaggerated.
... yes, as I said, the purpose is to inform further research based on it, because the reports showed a suspicious pattern. How is that relevant to the thread here with the "the vaccine killed 15000 people, because there is 15000 reports in VAERS" claim?
https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/ad...