For what it is worth, Epic has directional shadow caching disabled for Fortnite. To maintain performance they dropped the effective shadow resolution instead.
The tradeoffs involved in this decision will differ for other games. There is certainly a visual impact from giving up on shadow map caching and dropping the shadow resolution that may not be an optimal choice for other games. That said, we are reasonably happy with the level of quality we are able to achieve in Fortnite even with no directional light shadow caching at 60 fps, as it is still a noticeable improvement over previous solutions.