Well, blur doesn't end when you attack or cast another spell. That's pretty significant.Blur: Strictly worse than invisibility (a spell of the same level) in terms of both availability and effect. The only corner case where Blur EVER helps in a way that invisibility does not is against creatures that have see invisibility but not truesight.
Well, blur doesn't end when you attack or cast another spell. That's pretty significant.
They were two seperate examples. In theory craft land you don't ever get surprised or lack preparation, but in real D&D it happens all the time. We've had plenty of tough fights where we haven't had that minute time to prepare - and heal is versatile in the sense it's useful ALL the time.
Your example against Tiamat is flawed. Firstly by the time we found her we actually didn't have a minute to prepare, because we found the ritual to summon her first and we needed to act quick.
Secondly theres no guarantee the person I cast regenerate on will actually need it. I might cast it on myself, but it turns out our sharpshooter Fighter gets pummelled and needs healing desperately. I've now lost that tactical flexibility and ability to react to the combat as it develops, and as a result wasted a 7th level slot.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.