While it could use some protection (enter Temple Altisaur), being able to discover X once per turn based on the toughness of a Dino entering the battlefield is a huge play, and one that can snowball into an easy victory if your deck is stacked the right way
If a nontoken creature an opponent controls would die, instead exile it and you gain 2 life
To give your foe a basic land is indeed a downside, but a fair price to get rid of almost any threat
Creatures you control that attack planeswalkers that player controls or battles that player is protecting won't count toward Landroval, Horizon Witness's trigger condition
I also have a little graveyard hate in Sungold Sentinel, which also comes with the ability to get a weird pseudo-protection from a chosen color if I've got three or more creatures with different powers
And they're keeping the ball rolling into 2026