Yes, it’s points per shot. League average is about 1.2. Check it out.
When you compare players by position, you really see how inefficient some players are. Among forwards, he is #204 in EFG% and #207 in TS% out of 240 forwards.
Stats like offensive rating can be very deceptive because they are a measure of a player’s teammates. Wiggins is #32 in offensive rating, while Paul George is #34, and there is no possible metric you can find in which Wiggins is better than George.