+1 card +3 actions for $5 is pretty good. There are only 5 copies, but even 2 copies can sustain an engine fairly well. The fact that you could conditionally turn Bustling Village into +$1 +2 cards +3 actions (extra card from playing a fetched Settler and grabbing a Copper from your discard) is superb. It's almost a Super City, but Bustling Village trades the buy for another action.
There aren't a whole lot of cards that provide +3 actions on their own. There's Crossroads, but you only get the +3 actions the first time you play it. There's Fishing Village, but you get the 3rd bonus action at the start of your next turn (which you might prefer to keep a steady flow of actions). I don't think Crossroads could sustain an engine by itself, but Fishing Village has a pretty strong reputation. In fact I think it was recorded as one of the most often bought cards on isotropic when it was still up. tl;dr stuff that lets you play a lot of actions is good.
The thing is, there are 5 Settlers in the way, and Settlers is kind of a half-good Peddler variant. You get card and an action, then you sometimes get the equivalent of +$1 if you fetch a Copper in your discard. Early game this is useful, because hey there's a pretty good chance you have Coppers. Late game you probably won't want Coppers, so Settlers are going to fetch nothing. Because of the 5 Settlers in the way, Bustling Village has sort of the same problem as City; how often do you want to be the one that buys the last card that triggers Greater Cities or Super Cities for everyone else? If you want Bustling Villages and have some way to gain cards before buying, you could use that to get the last Settler and get started on Bustling Villages yourself.