I tried to use one in the past - lasted an hour on it then sold it.
I've now bought a v expensive jobby, stuck it in my hall, have a laptop stand in front and use Zwift to workout on it. I stick Radio X on pretty loud in the living room.
I actually quite enjoy it which has surprised me.
I put this mainly down to a few things:
1. The set up. Having it in the garage would mean going outdoors into the cold and lugging various paraphenalia from house to garage, no doubt forgetting this, that or the other. Now it's all within half a dozen footsteps from the sofa, and a few footsteps from the loo.
2. Stats - I have a trainer that accurately measures power and it links well with the Zwift app. As I'm a bit of a stats geek I need something that I can rely on stats wise and the trainer/zwift/Strava do this. I am finding the Zwift app a bit buggy though but will stick with it for a while longer.
3. goal - I've set myself a goal to raise my ftp over the next 2-3 months and it's pretty hard to do that outside, in particular at this time of year.