Would you accept a certificate issued by AWS (Amazon)? Or GCP (Google)? Or azure (Microsoft)? Do you visit websites behind cloudflare with CF issued certs? Because all 4 of those certificates are free. There is no identity validation for signing up for any of them really past having access to some payment form (and I don’t even think all of them do even that). And you could argue between those 4 companies it’s about 80-90% of the traffic on the internet these days.
Paid vs free is not a reliable comparison for trust. If anything, non-automated processes where a random engineer just gets the new cert and then hopefully remembers to delete it has a number of risk factors that doesn’t exist with LE (or other ACME supporting providers).
I haven’t used tailscale to know how well it works but as a current zerotier user I’ve been considering moving away from it.
I actually love the idea and it’s super simple to set up but has some very annoying pitfalls for me:
Pretty much all of the issues I’ve had were with devices that have to disconnect and re-connect from the network and/or devices that move between different networks (like laptop, phone). On my router, it’s been super stable. Point is, your mileage may vary - it’s worth trying but there are definitely issues.