For reasons outlined here (Intervals.icu hitting Strava rate limits - big consequences for TR users! - #2 by mcneese.chad), this feature suddenly got a bit more important - for most TR users intervals.icu will simply stop working soon.
I’m a triathlete and intervals.icu makes TR a lot more pleasant to use, because a lot of the data digging for running and swimming, load calculation, running FTP and power curve/pace analysis, and so on, can be done on intervals.icu while TR (very slowly) extends its own running support and integration.