It is a personal matter for everyone whether to receive a certificate. I agree that it is probably needed only for work in order to show it along with the rest of the certificates to the company that hires you. Perhaps you will look more competitive against the background of other candidates. As for knowledge, I don't know what it gives that can't be found in the public domain. I agree with you that on the forum you can find a lot of useful information.
The certificate only confirms that you have knowledge in this area. But the absence of a certificate does not mean that you do not know anything and do not understand
There is a conclusion, then if there is an opportunity, then it can be done, it will not be worse with him - it can come in handy