4* Defensive Shield vs 5* Defensive Shield? Any shield that isn't Barbarous Thorn Shield or Heater Shield

So upgrading weapons from 4* to 5* is generally not worth it when one does not have enough radiants to get it to level 10 or at least 7, right? And heating 5* shields is generally pointless because it won't add one extra hit's worth of defense right?
Does that mean upgrading a shield that isn't a snarboshield or heater shield to 5* pointless too? I'm asking mostly because Google failed me in my efforts to look for this specific question.

Yes, 5-star shields are defensively valuable for their status resistance.
Yes, heating them is a low priority. In particular, heat doesn't help status resistance at all.

Heating shields removes the worst penalty of all- a notification telling you that you need to heat something.

Well, that's bad news for me, now I really DO need to get Grey Owlite Shield. Good to know though, it's hard to tell because all the shields' status resistances have samey-looking stat bars
@Fehzors-Forum-Alt But i like that cute tiny yellow star next to my forge button, it tells me if i'm in a zone where I can switch weapons ;v;
The status defence increases from taking some status damage to total immunity to status damage.