It's a good strategy. With that small $5/mo. investment comes some credibility: you are saying, "I'm in this for the long haul. I'm serious about my writing - and my reading. I'm not just in it to spam the site, make a few bucks, and leave."

I've written before - I will follow back most followers who have the "paid member" indicator around their profile pics (Medium has made this slightly harder to find, to their detriment, I think). I will follow those who don't have it, too - but only if I first find myself reading more than just one or two of their posts, here.

Do "followers" matter here? To some degree, yes: you'll see more work from people you follow. Doesn't have a direct effect on getting paid, if your followers aren't reading your work or spending some time engaging with you, sharing your work more widely, etc. But again, that small investment in the site - throwing your $5/mo. into the kitty with the rest of us, to share in that revenue? That is a good strategy if you also want to earn.