I did the low vol Sprint Tri plans last year (base, build, specialty). I've been doing Tris for 13yrs but the bike workouts were always super hard on TR. It all depends on how YOU as the athlete respond to certain types of stimuli. I found the plan too intense, especially during racing season and dug myself into a hole which caused my fitness to steadily decline the 2nd half of the year. It makes sense when I look back on my training now, but it's hard to see in the moment.

The low vol plan didn't have any steady aerobic/AeT riding, and I've found I need more of that to improve fitness; & less of the super high end stuff. The VO2 max days (Tuesdays) were the hardest and wiped me out. The supra threshold days (Thursdays) always seemed doable but I found myself having to turn intensity way down just to make the intervals, which crushed me even more for my Saturday sweetspot rides as I was still really tired from Tues/thursdays. Compared to my bike times from previous years, I didn't have any power PR's during my races or any significant improvements on the bike, and that might confirm that this type of plan isn't the right one for me.
The application and functionality was awesome and TR is great, but it just didn't work for me. Lesson learned. I'm sure it works for others too, just not for me.