Magnificently so, yes.
The challenges are meant to be difficult enough that most players cultivate a deck just to beat a single AI persona, even if that deck is useless against general opponents for necessarily focusing too strongly on one or two aspects at the expense of others. Quite often, you have to exploit some behavioral quirk to be successful in a situation where a human player would have seen the danger and played differently.
Disallowing Rares (while still allowing you to draw them) is just one way to keep players from getting a lucky break. Consider taking Vulture
or something similar to at least get SOME use out of them.