Spatial with in-memory. Why have an index on points?

Since we now have some information on the basic scan rate with in-memory for the next version, going forward what is the purpose of (slowly) building spatial indexes and stats for point geometries, and then maintaining them both?

It seems there should be huge gains made on the spatial side using this feature, even if temporary geometries had to be constructed from raw x/y numbers to use existing library calls.

Can anyone comment on this yet? :-)

Bryan