What is blade ward good for, why is it better than the Dodge action?

[MaxWilson]

Well, it's the only cantrip that can target objects. And set them on fire.

Prestidigitation.

I'd honestly say the opposite. There are plenty of ways to get someone to attack you (standing near them or just straight dealing damage are generally the most frequent), there aren't many telegraphed defensive powers that are worthwhile. Barbarians can't Dodge because it risks making them lose Rage, Monks don't Dodge because Flurry of Blows (or another BA use) is generally already being used for your other Monk features, Rogues don't Dodge because they can just Disengage and Dash if needed, Casters don't Dodge because they either don't foresee much incoming damage or because they have a better solution. The only classes I ever see take the Dodge Action (and even then, very rarely) are things like Fighters.

Sounds like a playstyle thing. I often see situations where Dodging would be useful, both in actual play and in combat challenges posted here on GITP. That doesn't always mean the players see the opportunity and use it, but it's there.

In particular, it's good when you're already grappling somebody (e.g. a paladin, cleric or medium-armored bard) and there are other enemies around, and it's good when you want to occupy space to give other PCs protected terrain (e.g. occupy a corner position so another PC can lie prone without monsters being able to approach to within 5' of them and lose disadvantage--helps protect the other PC's concentration). You can even do both at the same time--grapple a monster and use it to help block other monsters. Bottom line, Dodging helps create asymmetry for the players to exploit.