The coffee thing is a vexed issue. But then, so is tipping people serving coffee. Here in Ozland we are not expected to tip, but many of us do, but usually for when the service is good.
So let's have a look at that. I have read many superb stories written by writers who are making virtually nothing on Medium (probably most of us here), so I guess, in a fair world, and if you can afford to do so, why not?
I personally haven't used the link, but I have never been good at asking for money.
I recall my daughter and her friend, asking if they could busk here in Canberra, play carols leading up to Christmas. They were both very good musicians, by the way.
They worked their little behinds off and I was proud to stand in the crowd and listen to them.
Later that day, at a neighborhood barbecue, I just happened to mention two things, the immense applause they got, and the tidy sum of money they made, to which the local doctor said: Busking or begging?
To be honest I was annoyed I asked if she ever went to concerts. She did.
"So I'm imagining it's different. The musicians would have practiced?"
"Precisely," was her reply, to which I said while collecting my things,
"Shame you didn't attend any of my daughter's rehearsals. The two girls met every weekend and practiced for hours to get thing perfect."
So putting a little addend about possibly buying struggling writers a coffee, is in my books, an okay thing to do. Perhaps if we all did it, and it came to be something we all expected it would put to bed the shame factor...if in fact there is any.