This is a very promising announcement for Unreal game development specifically. For any other purpose I wouldn't care as much.
Perforce definitely needs a challenger. It is not the incumbent because it is particularily simple to use or administer. Git is actually way simpler when it comes to branching operations for example.
The reasons why p4 is often preferred in gamedev have already been mentioned in other comments: large project support, permissions, file locking and so on. Another key reason p4 is the king for Unreal dev is just how well it's supported inside the engine. Not perfect, but it's the best supported VCS because it's what Epic uses. Even the Git plugin is painfully unfinished, because Epic does not internally use it. So with Lore I expect them to give it first class support. I'd recommend Git a lot more if the support in Unreal was better.
(background; I've been in gamedev for almost two decades now, 2-200 person companies, every kind of engine and version control system. I prefer git where I can use it: for Unreal that means small projects and/or tech savvy team members. Pick the tool that is right for the job and the team.)