They way I read this, Edge replaces SBE and SBE will no longer be available (in the future).
Edge lets you use only 4 cores instead of 8 for SBE (Edge boasts unlimited "CPU chip" count, but that's useless/irrelevant if only 4 cores total are allowed per host)
And although Edge allows unlimited database size, in practice, larger databases need will need to use a few cores for running backups. So if you need 2 stripes to get good dump throughput, that will use up 2 cores, and the dataserver will be effectively limited to remaining 2 cores (ie., 4 cores minus the number of dump stripes)
So Edge is really for smaller applications than SBE. But there all the extra security, encryption, and partitioning features available in Edge.