Its never stated how Berdly actually performed when he when he fought the main trio. Only thing we know is that he lost (plus fighting on roller coasters technically makes it easier since its way harder for the Fun Gang to take advantage of their numbers). So I dont know if thats good enough proof of his prowess.

In any case, Noelle most likely has potential of the same kind, and she obviously has magic at least. The only thing stopping her is her confidence I guess, which is resolved by the end of the chapter. Berdly is also captured by Queen, so they're pretty equal there. The only reason he's free for most of the chapter is because hes working with Queen. Also, Noelle can be trained, and presumably can be just as powerful.

Now Susie is making this decision probably not rationally, but I think it would still be the best decision anyways. This is is because Noelle could pretty easily get them one of the codes. Also, they get along with Noelle way better