I think thats good advice for anything, I would however put the caveat on things that use open protocols. I have no issue using AWS SES (Simple Email Service) because thats just SMTP, I would however never use something like Firebase. Just measure the time it would take you to get rid of it in a project.

I would also never use the sentiment shared on HN much for anything, half of the people here have a stake in their own little proprietary technology they want you to sell :P