I have recently in my dev build clarified the documentation a bit
If toggled, graph updates will batched and executed less often (specified by #maxGraphUpdateFreq).
This can have a positive impact on pathfinding throughput since the pathfinding threads do not need
to be stopped as often, and it reduces the overhead per graph update.
All graph updates are still applied however, they are just batched together so that more of them are
applied at the same time.
However do not use this if you want minimal latency between a graph update being requested
and it being applied.
However this throttling currently only applies to graph updates applied using GraphUpdateObjects. Navmesh cuts are internally applied using a different mechanism (WorkItems, a lower level scheduling primitive that the A* Pathfinding Project uses) so navmesh cutting would not be affected.
One thing to note is that if it would have been affected by the throttling and you would have set it to 15 seconds, then all graph updates during those 15 seconds would be batched together and applied at once. That is probably not optimal since they would only override each other, so the setting on the TileHandlerHelper is the best place to adjust it.