I think they took this particular license because it could easily be translated in Playmobil and they probably hope to bring in some fans of the franchise.
They already know how to make a fire stations and vehicles so they'll probably reuse some items they already have.
Maybe they're trying licensing since it's what saved Lego in the late 90's. If Ghostbusters turns out to be a success for them they might go for other themes.
In the end, it won't stop them from continuing their regular lines, so I don't think collectors have anything to fear from this change of direction.