Maybe because they are proven capable to deliver technology team, which Google has many ways to employ, that was about to be unemployed en masse given that Homejoy was suspending operations and thus likely wasn't going to have much for them to do, or anything with which to pay them.
> Home services seems like the sort of thing that absolutely demands a solid customer service and sales organization.
If Google, as was reported months ago, is well on its way to offering its own product in this market than, whether or not Homejoy's tech team was (as is claimed, without any stated basis or source, in the Re/Code article) hired to work on it, its likely that the customer service and sales structure for it is already decided. If the model isn't fundamentally what Homejoy was doing, there's not necessarily any reason to think that Homejoy's team in that area would be of any use to Google's product.
OTOH, whether on a home services product or otherwise, Google probably can find lots of uses for engineering talent.
Perhaps they are paying a little premium on hiring themselves to get a single team started and working on something very quickly?