If a particular training schedule is motivating to a person, and it encourages them to ride regularly, it’s not surprising that they see some benefit.
That being said, Zwift racing (or outdoor group rides) will not come close to a structured training plan in terms of consistently and accurately stimulating the different energy systems you need to be a dynamic rider.
Fortunately you can do both.
Structured training on TR + occasional doses of group rides/Zwift races/etc
If you want to do both, just use a TR Low Volume plan for Base+Build+Speciality and then go race on Zwift or do group rides to your heart’s content.