Your question was do you need them, my answer is I'd want more (thus yes I do need them).
I don't need a million dollars but I'd want a million dollars so I'd say no you don't "need" them you technically don't need any but they are a nice convenience.
You see some of these I just have on my characters since you get multiple in abundance (black lion salvage kit and birthday boosters), also I find it weird that you have all this stuff but no infinite gathering tools. But I get it they are really useful to have and it's not like I wouldn't fill mine if I had more but as I said before 25 feels excessive and your list kind of is excessive imho. Also the fact you have Permanent Bank makes the amount of shared slots you need irrelevant since you have bank access on all characters from anywhere .
Yeah plenty of stuff to put in them, not even close to done especially with permanent contracts. https://imgur.com/EXcyiNf