You're not always looking at a map at all times though. If I verbally tell a friend "Let's meet up for lunch at Westville Chelsea", they can then unambiguously locate the exact one later on on their own.

Also, lots of people (especially visitors!) don't know where the neighborhoods actually are. So having the names of the locations in the pins is better than them struggling to figure out exactly which of a series of identically named pins is actually the right one in an area they don't know about.

Problem is the same name is also used for lists of search results – having a neighbourhood name being displayed there can definitively be helpful to distinguish multiple branches of the same company, while also having a higher chance of being at least roughly recognisable to people as compared to specific street names (which is what Google currently displays for POI listings).