I instinctively distrust any software or protocol that implies it is "simple" in its name: SNMP, SMTP, TFTP, SQS, etc. They're usually the cause of an equal or more amount of headaches than alternatives.
Maybe such solutions are a reaction to previous more "complex" solutions, and they do indeed start simple, but inevitably get swallowed by the complexity monster with age.
TFTP is probably the exception to that rule. All the other protocols started out easily enough and added more and more cruft. TFTP stayed the way it's always been - minimalist, terrifyingly awful at most things, handy for a few corner cases. If you know when to use it and when to use something like SCP, you're golden.
If TFTP had gone the way of SNMP, we'd have 'tftp <src> <dest> --proto tcp --tls --retries 8 --log-type json' or some horrendous mess like that.
TFTP's usefulness in the modern day is strictly for things that don't have a TCP stack. Anything with a TCP stack is better off with HTTP. That doesn't leave much on the table except legacy & inertia.
Maybe such solutions are a reaction to previous more "complex" solutions, and they do indeed start simple, but inevitably get swallowed by the complexity monster with age.