That is clearly false. The blue check was an accurate signal of authenticity through verification by Twitter. What it was not was a universal verification mechanism that scaled to being able to verify everyone who used the platform. Those are two different things, and the lack of universality does not mean that the programme was not useful in valuable in providing a means to prove authenticity and avoid impersonation of the many people it did cover.
Moreover, the company was actively working on ways to scale it up into being able to reliably verify many more people before Musk bought it.
Now all that is gone, and a blue check means nothing to other users of the platform other than as a sign that the holder is paying for premium features. It's no longer a trustworthy verification mechanism.