I used repl.it for a class and it worked out nicely, where I could set up a template with data and code and the students could fork it. The one thing that made me not renew past a month is their receipts say "Hacker" on it as your purchase (it's one of their pricing levels), and it was awkward getting a reimbursement from the university for that. Even handing a receipt saying that I purchased "Hacker" (without much context) made me hesitate.
I also suspect if people are linking to it in tutorials as a way to get an immediate environment there might be a lot of new signups that don't stick around.
Is anyone on HN using this consistently day-to-day for something?
I definitely don't see myself ever needing to pay for their product. I'd guess the play is to get into B2B or EDU as a hiring or education platform.
I'm reminded of a project a while back where the business only cared about user acquisition...not retention. It does not exist any longer, and was never profitable. But they exceeded their target numbers every quarter (until it was killed by upper management for having no path to profitability)