Sure can't hurt. One of my friends is among the fastest local cyclists, although he doesn't race. He's top ten or KOM on many local segments. Last year he started Zwifting more often, at least on the hottest summer and coldest/wettest winter days. When he does go outdoors for rides he's as fast as always, maybe faster. He's beaten some of his own best times and has shoved me farther down the list on the few where I've cracked the top ten. I think he's in his 50s and rides like a much younger man.
I just use an older Cycleops without any software, just Wahoo Fitness as a timer for intervals. It didn't improve my road speed but helped me maintain fitness last year when I was injured and ill most of the year. So I can see how a structured program with incentives could motivate us to get stronger -- even if the techniques and feel don't match a crit. I haven't raced crits since my teens/20s and don't plan to again so it wouldn't matter. But I'd like to try time trials. I'd need to work on sustaining 300 watts over distance. Judging from my Strava data I tend to sag after 5-6 minutes, even though I probably had more in the tank. So the unstructured trainer work isn't quite enough to push me.
Another friend used Zwift almost all of 2018 after she was badly injured when a dog knocked her off her bike. She only recently resumed cycling outdoors again and didn't lose any fitness. She doesn't ride particularly fast but found some casual ride Zwift groups that encouraged her to stay fit, which is terrific. Good for her self confidence.
Last edited by canklecat; 01-09-19 at 02:18 AM.