I don't think people questioned whether she created the beats. They just assumed the people she brought in who were known for doing beats did the beats.
Billboard, 2001:
Quote:According to Bjork, the bulk of "Vespertine" was recorded not in a studio but on her laptop computer -- which explains its strangely homespun, diary-like air. Also, Bjork confirms that most of the album's beats aren't from drum machines but from objects found around the house, "like a deck of playing cards." The set's first single, "Hidden Place," even features what she terms "poker-style card-shuffling."
Wikipedia:
Quote:Matmos gained notoriety for their use of samples including "freshly cut hair" and "the amplified neural activity of crayfish" on their first album[3] and "recorded the snips, clicks, snaps, and squelches of various surgical procedures, then nipped and tucked them into seven remarkably accessible, melodic pieces of experimental techno" for their album A Chance to Cut Is a Chance to Cure.[4]