Getting Siegfried to NP5?

My personal rule of thumb is to never ever burn any servants until I NP5 them (which includes my NP2 Stheno and non-existent Fionn (as of now) and I do love them as a character but listing them down anyways since he's divisive as a character and low-tier, NP3 Astolfo)

The biggest increase however is already in NP2. Siegfried also gets a strengthening down the line that massively improves his effectiveness and NP spam too with NP up effect.

If you missed a mystic code or CE and want them in the shop in the future, won't lose too much on making his extra copies Rare Prisms since NP2 is pretty strong on its own already. Though I'm still personally leaning on NP5 just to squeeze out every bit of strength.

You can destroy almost everything now with NP 5 Siegfried.
Basic team of FGO is 2 supp + 1 DPS or 1 supp + 1 tank + 1 DPS.
With Sieg+George+insert supp here virtually you have no weakness and the team cost is cheaper.
Count Siegfried damage modifier first before you burn him !
With 1 Georgios( dragon mode first ) you can get 80 % bonus damage + Def 30 % for 3 turn with 5 turn CD and his NP 5 can obliterate neutral enemy like it's nothing.
Other saber with 1 waver only raise their damage to 30 % for 3 turn with 6 turn CD.
And imagine you use Merlin, Waver and if you don't have both use Shakespeare Buster buff.
Also he is one of the strongest saber with Buster up 50 % for later.
Seriously you burn monster like him?

Go see Siegfried and George destroy Scathach and Cu Cullain in Nerofest first before you decide to burn him

https://youtu.be/os6KKTQIkB4

I’d say NP5 is more worth it than a few rare prisms for any servant