I'll never understand the idea that there is any other criteria, let alone some weird idea of 'worthiness', than 'can we sell this by attaching this person's name to it'
Recently internet famous or not, if Fender think they can flog enough of it to her fanbase to make it worth their while, and attract non fans with a fairly unique pickup config and finish amongst the current fender range, why wouldn't they?
Edit: In case it's not clear I'm not against this, or any signature bass for that matter. I think it's great if any bass player is popular and influential enough that companies like Fender want to work with them, especially if they're attracting a demographic that previously wouldn't have considered picking up a bass. And I really like the tweaks she's come up with for her sig.