The only metric that matters is how many workouts did you do today, or this week. Unless perhaps you're planning on entering some sort of competitive spinning event all those numbers don't add up to anything.
I get that I'm not Peloton's market (they don't care about nerds who build their own kit, and that's probably the right choice) but I 100% understand why this stuff matters.
Not if you're actually serious about going faster on a bike. Power data (as provided by basically any non-Peloton smart trainer) is incredibly useful in maximising the effectiveness of workouts and measuring your fitness. A high-end smart trainer like the Wattbike will also give you data on power delivery through the pedal stroke and left/right power balance, which has real implications for performance.