Well, truthfully, I happen to be a product guy looking for a job, and I really wanted to kick the tires of both Fly.io and Tailscale to see if I'd enjoy working

Well, truthfully, I happen to be a product guy looking for a job, and I really wanted to kick the tires of both Fly.io and Tailscale to see if I'd enjoy working on either. @QuinnyPig's tweet connected the dots for me with a use case that's 1. actually useful, 2. easy enough to build in a few hours, and 3. tailor-made to combine both products. So, not exactly a coincidence, but hopefully not shoehorned either. ;)