In the vast majority of cases where you have feature teams, the designer (if there is one) is a graphic designer.  It’s not that graphic or visual design is not important, but what’s relevant here is that now there’s a big gap – someone needs to figure out at least the interaction design and hopefully do some user research.  Hence it’s very common to see pressure on the product manager in this model to try to fill these gaps.

If you are fortunate enough to have a true product designer on your team (at least until they leave to move to a company where their skills are able to be fully utilized), then they usually (and rightfully) question what the purpose of the product manager is, as it’s not hard for them to pick up the additional responsibilities of the feature team product manager as they’re doing the bulk of the work anyway.