Google's John Mueller said on Twitter, "when it comes to web pages in Google Search, hashtags are just words, they have no special meaning or effect." So if you are big into #hashtagging everything, ...
The primary benefit of using keywords over hashtags is intent. Hashtags are often too broad (#Marketing) or too niche ...
I don't think it matters if you use hashtags in meta descriptions or not. I mean, it might be more eye catching if Google uses your meta description for the search result snippet - but maybe Google is ...