Good point. It is a bad idea to set up something as lasting as email addresses with a somewhat proprietary solution by two commercial entities and stray from pure standards. Temporary convenience turning into long term lock-in is a poorly understood issue, especially by people that don't necessarily have a technical background.

I have used aliases to catch spam and have gathered about 200 email aliases this way over the last 12 years or so, and it works well. Rather than using a catch-all, I manually create the alias with a script.