Are signs too weak to invest in?

Hello everyone! Started witcher 3 for the first time. I wanted to do a build where signs are my main strength. Is this a bad idea? They seem quite underwhelming?

I ve played a bit with all of them, but 95% of the time I use quen and igni.

Igni does almost no damage at all. Quen is quite usefull, but even weakest enemies destroy it in 1 hit.

The way I see it, there s no point in investing in them at cost of literally anything elss, because even if I get 200% sign intensity, they only are marginally better.

Upgrading attack power seems much more usefull, 50% extra attack power is MUCH easier to get, and waaay more useful on my basic swords that already outdamage signs by a lot.

Or the alchemy tree which gives me alot of extra health.

Out of all the upgrade trees and mutagen slots, signs seem by far the least worth it.

Am I in the wrong here? If so, I am sorry, but I am a complete beginner. I don t want to play 20 hours only to realise I don t like my build and have to restart.