it's all endurance and a continuum, it's just a grey area. other coaches I know advocate for riding "z2" easy and focus on time and not the exact power (if anyone follows Empirical Cycling, Kolie Moore and Rory Porteous do not prescribe an intensity for endurance, but will counsel athletes on staying below a certain level). and if they want you to go harder, they'll prescribe sweet spot and above. That's not to say there isn't a place for long tempo, it's just doesn't add as much value as just riding easier or just riding harder. That said, i've personally done, for example, like 2x60 at 85% in a longer endurance ride just to practice being at that level as a way to prepare for my annual solo century PR attempts, for which I try to maintain over 80% for 100 miles.