While riding indoors can be mentally challenging there are massive fitness benefits to be cultivated by spend time in the "pain cave".
On an indoor trainer you are constantly applying pressure to the pedals, the work is steady with little to no interruptions, you are almost doing 50% more work than when compared to riding outdoors for the same amount of time, add structure and you get a bigger bang. Another reason as to why you should ride on an indoor trainer is that you will be able to work the same muscles for extended period of time, this is good provided that you change your body position both in and out of the saddle to prevent certain muscles from being over-worked and others to be under-worked.
Training indoors can be highly productive when done correctly, whatever your goals may be always follow a plan that incorporates the right type of workouts that are based on your limits and strengths.
Here are a few guidelines
Limit the riding time from 60 to 120 minutes.
Include off the bike training, such as push-ups, squats, planks, etc.
Never just ride in Zone 2.
Don't skip the cool down.
The indoor trainer is a valuable tool, aim for quality over quantity.
That is it, thank you for reading, I hope you found it to be a useful resource.