Training on a bike indoors is mental torture. Anything to help distract you and trick you into putting down power is a good thing.
The most common (non-peloton) method is to buy a) a stationary trainer and b) a
power meter for your bike.
This allows you (or your coach) to structure your your indoor workout with sets, such as 10 x 3 minutes at 275 watts with 1 minute rest. It's similar to the idea of a spin class, but without the screaming cheerleader / instructor. Sets with shorter, higher intensity intervals are much easier mentally when indoors than long steady-power rides, yet still very effective at improving your bike fitness.
The nice thing about the power meter route is that you can also use it outside every time you ride your bike. Even if you're not doing structured training, it's still fun to have. You can use it as a guide while you ride (eg, "Last time I tried this hill at 300 watts and I hit the wall before I made it to the top. Let me try 280 watts this time and see what happens"). You can also ignore it while you ride, but analyze the data afterward. The software produces some really neat graphs that help you track your progress over time.
I'm a big fan of power meters on bikes. They're a lot of fun, particularly if you're a numbers weenie.
Of course, nothing's stopping you from having both the peloton and getting a power meter for the bike!