You can now Get Traced Distance At No Extra CPU Cost!
Epic accepted my pull request to expose Distance information as part of FHitResult!
The PhysX engine was always returning this information, so my requested Engine code change did not affect performance at all.
The advantage is that now whenever you do a trace, you already have the non-squared actual distance from the start of the trace to the impact point available to you!
Trace Functions Wiki Updated With Info About New Distance Property of FHitResult