The vast majority of these imposter land cards don't quite get there in most cubes. I'd say the only one that interests me is the Landfall Elephant, but even then it's mostly as just a beater to push through damage. In a lower powered format utilizing bouncelands however? I think these are incredible for that kind of environment if board development is slow enough.
I think that is a gross underestimation of these cards. As the average power level of a cube increases, the value of modal cards also increases. In a low power environment, modal cards often aren't as important as in high powered environment, since games are normally longer and players will have more time to use all of their cards. Thats why decks like Aristocrats and +1/+1 counters have a tendency to work in low to mid powered cubes but not high powered environments- more time in the game means more chances to see and play all of a decks interactive pieces.
The problem is that, in high powered environments, games tend to be quicker. Aggro decks are more efficient and more streamlined, midrange decks start pooping out planeswalkers on turn three, and control decks have the most efficient counter magic and removal possible. Here, decks can't afford to run slow or narrow cards because they will never get a chance to use them. However, that doesn't mean they don't
want slow or narrow cards, just the material conditions of the format makes it impossible for those cards to always shine. Green ramp decks would love the ability to play
Regrowth in many games to bring back a key creature or planeswalker, but can't always afford the slot because the card sometimes ends up never being used. By stapling
Regrowth to a tap land, a green player now has a way to play their
Nissa, Who Shakes the World for a second time when she dies, without ever having a useless spell in their hand that they can't use effectively.
I'm not saying these cards will get there in cubes with the Power 9 where dozens of slots are dedicated to niche combo pieces and storm cards. However, I think "tasteful powermax" cubes focusing on keeping a narrow power band at as high of a power level as is reasonable will run as many of these as possible. There's only like 5 or 6 of these that high-powered environments wouldn't want to play.
I'd recommend looking at John's prospective includes for the Cultic Cube and Eleusis to get an idea of what high (un)powered environments want to run from this set. It might not convince you that these cards are good in practice, but it should hopefully help you to understand just how many of these are at the very least interesting to people running at high power levels.