Why would you need a dedicated graphics card in a server? Usually you wouldn't even have a monitor connected.

I have an NVidia Tesla P40 in my home NAS/media server that I use for video encoding purposes. It doesn’t even have any video outputs, but it does have dual media encoders and a decent amount of VRAM for lots of (relatively) high quality simultaneous transcoding streams using NVENC/NVDEC to re-encode 4K Blu-ray remux’s on the fly.

My guess would be video encoding/decoding and rendering.

Some Intel and AMD CPU come with an iGPU that you can use to transcode videos even some Xeons, there's no need to add a GPU just for that

A lot of them don’t though. My Xeon doesn’t, so I threw a cheap used Nvidia Tesla P40 in there to do the job. Also it can handle a lot more simultaneous streams than any iGPU I’m aware of.

Some people are tired of rendering everything on the CPU via AVX.