If a spell destroys one of these land types, this card is destroyed
There are some stipulations, however, but it's relatively easy to meet them
This type of effect is most powerful in mono-black, where you'll have a lot of Swamps to play with, but can also be very effective in simple dual-colored decks
I also like that both Questing Druid and Virtue of Loyalty are great fits for this game plan on their front side, helping the deck to go tall and even threatening to steal some games with the fun-of Voldaren Thrillseeker
These cards have held their value pretty well, unsurprisingly
Other mobilize cards also turn into great card draw, but there are lots of effects in the wheelhouse of Mardu's color combination that bring in temporary attacking tokens like Fire Navy Trebuchet, Urabrask's Forge, and white does away with the temporary nature altogether on Adeline, Resplendent Cathar