Traditional non-cloud, non-weird DNS providers have sufficiently long TTLs, not the "60 seconds and then it's broken" crap that clouds do to facilitate some of their services.
Something like TTL 86400 gets you over a lot of outages just because all the caches will still have your entries.
Yes, of course. But you usually don't put your important webserver doing bazillions of requests per short interval on dynamic IPs. Especially if you need to avoid any downtimes.
Something like TTL 86400 gets you over a lot of outages just because all the caches will still have your entries.