Interpreting the keywords is up to the search engine, but the most expected practice would be that the comma-separated keywords are all distinct, so no, the two examples you write would not be the...

Google is, in fact, using meta descriptions in SERPs as of this writing. What they may not be doing is using meta descriptions that are abusive, keyword-stuffed, etc.

Meta tags are certainly not going to stop being relevant for as long as Google continues displaying the meta description in SERPs. The text that appears there is your 'creative', as it's called in...