3 hours of battery working out! ROFL!
This is why you will never see a triathlete with an apple watch.
What other option do you have for streaming music and workout? I have a Gear S3 which has been rated very good for battery life and I don't get a lot longer than this if streaming over LTE with Spotify and working out. I think I'm at about 4 hours just doing some extrapolation. If I needed to go longer, I'd just listen to downloaded playlists. I expect a triathlete doesn't have to stream their music.