If all there were were numbers and charts, I'd lose interest really quickly. It is how the apps keep you engaged that makes them worth the money. I stay engaged with Zwift in group rides because there is chat, the desire to stick with the group and the desire to finish. With The Sufferfest there is the motivation in the video. Yes, you can do the same rides without it, but I'd probably give up after 15-20 minutes. I've tried doing rides using just the bike computer but never finish. I've owned a trainer for about 20 years now but only in the last year with Zwift and The Sufferfest did I actually use it more than once every blue moon.