Awesome idea, thanks DJ.
So I'll be the first to admit that I'm not very well versed when it comes to Land. I fomo'd into a Tract at some point so I have some representation there, but I haven't spent time thinking about the Land economy very much.
With that said, I love this idea from the point of view of helping the Card & Pack economy. I don't really know whether it's the right tradeoff, but from my point of view it makes sense as the overall PP being burned, if I'm not mistaken, it considerably less than the total PP potential being created. Of course the latter is more concentrated, but in general it seems like a good tradeoff.
I suppose one consideration would be whether these cards take away from the value of other cards (e.g. gold foils, alpha/beta) who are typically your higher-concentration PP cards. Personally I am not overly worried about that, but it's possible others might be opposed to the idea because of that.
I also really like it conceptually. I think the "land giant" idea is cool and lore-appropriate.
I am not invested in land either but, I'am thinking if the ability of these giants could be such that - on land, they boost productivity by 10%, and in the game, they add the earthquake rule set (it affects both sides but u control the narrative)