That we can calculate the distance to a lightning to great accuracy (my example in the very first sentence) by accounting for a finite speed of sound only and a

That we can calculate the distance to a lightning to great accuracy (my example in the very first sentence) by accounting for a finite speed of sound only and assuming an infinite speed of light? Yeah, I'm pretty serious that we can neglect that error of some microseconds when concerned with a process that takes many orders of magnitude more.