Plans I see for time crunched athletes tend to do more Z3 plus higher zone intervals, so I think your take is valid. I train for XC MTB (my A-race is 60miles ish) and ultra distance, so maybe the Z2 work is more important for me.
However, this is all beside the point - whether it makes sense or not, there are a lot of folks doing polarized plans that involve a lot of Z2, so the desire to be able to type while on the trainer isn't unreasonable.
However, this is all beside the point - whether it makes sense or not, there are a lot of folks doing polarized plans that involve a lot of Z2, so the desire to be able to type while on the trainer isn't unreasonable.