use them. I don't use indoor trainers but I am a big fan of applying a variety of training methods. you will gain something from it. even if that something isn't apparent right now. but someday, at sometime, you will be racing and something will happen or you will do something, and something will click and you will recognize where it came from.

for me swimming in a pool even though I have access to outdoor water lets me concentrate on form much more than when I'm outside dealing with environmental issues. but you know that already due to your experience with your trainer. if I had access to some other kind of pool I would use it. I also do weight training and use various movements for the same muscle groups.

anyway - you bought it - tear it up