VWAP is nice for many reasons. The first, is that this is not just an indicator, but a market. Broker dealers will transact in listed to facilitate clients paying/receiving VWAP. Look up Guaranteed VWAP for more information. Execution algorithms are using it for various purposes. For this reason, it can be used as a way to measure how aggressive buying and selling is. It's also a way to compare the after hours action with what happened during RTH.
I always have an area chart like this on one of my screens.
(VWAP with standard deviation bands)
-this is a chart of ES during RTH and the overlay is an NQ/ES spread-
[an index spread is the differential of indexes]
can trade it with long/short exposure via front month contracts
I like it because it's like a filter for price action trading. If the market is rallying hard and VWAP is going nowhere, that might indicate the move is going to be very short lived. On the other hand, when VWAP moves you know some pretty good size got done.
Price action relative to VWAP can give you insight into market context.