As someone else mentioned, Jill is a great Green party candidate for Democrats because she sucks. She's not that young, has Russian baggage, and isn't the new face that could make the party more popular. The philosopher dude, West, seemed a bit more dangerous, but Stein being their nominee drills in the fact that there are no viable 3rd parties. The real strategy has been that of the DSA, where they promote their own candidates within the two party system. It's both realistic, and far more effective than throwing your vote away.
The only people who will vote for a known spoiler like Jill Stein are to far gone to have really been potential Biden voters.