I know wave riders want slow boards so I'm assuming toe-in was invented to act as brakes so it's good for those conditions, but nothing else !
Sorry, but this is not a good assumption.
It's about the flow of the water under the board.
When a board makes leeway, toe-in reduces drag.
When a board is heeled, cant maximizes lift.
Compare to racing yachts, specifically the open class ocean racers.
They have toed-in and canted daggerboards.
This is not to create drag.
Interestingly, these yachts have the flat side of their daggerboard foils to the outside,rather than the inside as on boards. This is because they heel to leeward, not to windward like a board does.
In both cases, the design is about how water actually flows around the foils, not how we think of ourselves as "going in a straight line," or "trying to stay in the pit, etc.
Watch some riders, or videos, pay attention to leeway angle and edging, it will open your eyes...