If you want to improve your technique while riding indoors, the usual recommendation is to get some rollers. I plan to someday.
I don't hate my trainer, or love it for that matter. Because I'm coming back from injuries, I'm happy for any session on the bike. I put the trainer in front of my TV or computer and do some channel surfing or watch cycling videos. The time passes just fine.
I got outside yesterday for a ride on snowy, slippery roads--but it wasn't arctic cold, and not much traffic. That was good, too. Any time spent on the bike is good, in my view.