Why are there so many mods for minecraft that are only useful online when no server allows them?

For example you have the trap mod which would be really cool on a pvp server, but i don't need spikes to pop up from the ground for zombies when i can use and iron door and have a nap.

if you know of any servers that allow mods can you please link me i can't find any.

It's not that they don't allow them, it's that they have to add the mods to their server which takes time, can have a lot of bugs and they won't be able to keep up to date with the Minecraft versions. Mods take time to update to newer version, so servers would have to wait for it to be updated before they can then update which defeats the point of a public server.

These trap mods are designed to work with other mods, I'm running a modpack which has very dangerous mobs outside, without traps around my base it would be destroyed and riddled with insanely difficult mobs. Not many mods are designed to work on just a standard vanilla minecraft world, to experience them properly you need other mods with it.

These trap mods are designed to work with other mods, I'm running a modpack which has very dangerous mobs outside, without traps around my base it would be destroyed and riddled with insanely difficult mobs. Not many mods are designed to work on just a standard vanilla minecraft world, to experience them properly you need other mods with it.