If you subscribe to a good one not only do your torrents download faster, you're more immune from your ISP if there are any troubles. At the same time, you also upload better and use less of your own bandwidth. If you don't care then I suppose it doesn't really matter.
It's really just paying for something I don't need. As far as I know, downloading subbed anime isn't breaking any laws, so my ISP should have no reason to care. I also don't have a limit on my bandwidth anymore, So I can seed at my leisure.
I used to be limited to 250gb a month, but that was removed when my internet speed was upgraded in October. I went from ~190gb to ~450gb a month.