I had a coach for some training plans when I was timetrialling. As you say, it helped me get the most out of limited time available, but it took a lot of the fun out of riding my bike as it wasn't easy to move the sessions about too much – if its a nice day you just wanna go and ride your bike for a couple of hours, but the plan might be to do a short tough session.
Depends what you want, if you are training for a race/event then go for it, if you just wanna go faster/get fitter then maybe swap plans with a mate and report back on how you are going to said mate – this will help the accountability part of it.
Good luck