I guess I'm the one who don't understand why anyone need D-mods on their ships bcs as I know they give negatives and everyone trying to avoid/delete them.
Explain pls why it's needed?
The Derelict Operations skill encourages to field a D-mod infested fleet because each D-mod reduces the DP of a ship by 6% per D-mod (since you can have up to 5 D-mods on a ship, it means -30% DP for a ship, allowing you to field a huge armada, for example an Onslaught will only costs 28 DP to field instead of 40 DP). Derelict Operation is a very very powerful skill. In the modiverse, there's also HMI junker ships which get more "powerful" the more D-mods they have.
On top of that, some D-mods have very little consequences on the actual performances of a ship while others can be absolutely terrifying (the D-mod that reduces your PPT on a Safety Override ship for example). However, which D-mod you get is entirely random. If you are lucky, you can get 5 D-mods which will have little consequences on the performances of a ship but if you are unlucky, you can get 2-3 devastating D-mods.
In vanilla, you can circumvent this problem by "fishing" for "good" D-mod by restoring a ship, letting it die on purpose, checking its new D-mod, etc until you get 5 "good" D-mods. But it's expensive and very tedious to do.
This mod allows you to get the desired D-mods you want. If you don't like Derelict Operations fleets, you don't need it.