Sorry this slipped down the page here before I saw it. There is some value in higher intensity work for long duration endurance activity but not nearly the same way as for short duration rowing. This is primarily for 2 reasons in my mind. The first and most obvious is the relative intensities for an all day event is just so low that youre almost always well down in Zone 1/2 and primarily fat burning. The second is that much of mountaineering takes place at high altitude where the reduced oxygen environment makes upper HR Zones effectively inaccessible anyway.
The first article below does a good job of explaining how the aerobic system is so valuable as it is actually the one responsible for clearing excess lactate and why a really well developed aerobic capacity is actually your best friend for very high level effort.
The second link here has some data discussing the fact that upper HR zones arent accessible at altitude regardless.
Since a lot of things we do in the mountains are pack weight related we do find the ME type work here that your talking about quite valuable. I suspect its more from a muscle fiber recruitment and neural pathway development perspective than anything else. When your training by carrying a very heavy pack with high intensity like this in training a lighter pack and lower intensity will be much easier and your movements will be very economical.