Is backpack useless most of the time?

[Asparagun]

The title. What do I use it for? Besides the pack mutations (I'd rather not choose a mutation that might end up actually being useless), it doesn't seem all that much good. I see very little incentive to actually use the weapon I store, since normally the weapons I have work well enough.

[Fel]

It depends on your play style and difficulty.

In higher difficulties you are often rolling to avoid damage, those mutaions add additionnal value to that.
Since they scale with the related stat and have no cap they can be a great addition to builds that focus on a stat and gets as many scrolls as possible for example.

Pretty much all mutations can be good, it just depends on how you play (even the revive mutation can be good when trying to learn a new zone or difficulty).

[Uncle Fester]

Immo it is great for tacctic builds, you can basically add an estra effect to attacks, imagine it with bois axe, or alchemical carabine

[esco1979]

Armadillo pack is GOD TIER on 4-5 BC. Ice Shield, or Rampart in particular. Blood shield too if you find one that spreads bleeding.

[Soulfire72]

I also find that sometimes having a shield is just flat out more effective against bosses. Eg. if you normally use frost blast it's pretty much always a good idea to replace it with a shield temporarily when fighting any boss.

[Path]

I haven't tested it, but theoretically you should be able to use it to have the Giantkiller available for boss fights (drop it at the start of a level, play through it, teleport back, pick it up and put your main weapon in the backpack before moving on). IIRC the wiki suggested that as well.

I'm also partial to having a shield out for boss fights, though.