Not just their fiduciary duty: it makes the product better for end-users. Crowd-sourcing data on local businesses gives them a lot fresher and more granular state than they can get with an army of paid scouts.
There are apparently many, many 'end-users' who feel it does not make a better product for them, but thanks for being such a brazen apologist for shady practices.
Quantify "many many," and compare it to the user count that enjoys having Maps know fine-grained detail about the neighborhood because volunteers answer the questions it asks.