Urborg, Tomb of Yawgmoth has the static ability that all lands are Swamps in addition to their other land types, Radiant Fountain has the triggered ability that it gains you two life when it enters the battlefield
Nothing about this builds up anything, just eats away at resources, whether your opponents or your own
This in turn can push interest beyond what a comparable regular MTG product is capable of over time, especially if there are restrictions on reprinting the carts featuring the third party intellectual properties in question
Take 30 minutes to read through the seller guidelines of the platform you choose
Both are cards that rely on you surviving the early game, however, which is easier said than done
Perhaps its because this card can force unenjoyable play patterns