64-bit Kernel Question

[Petrus de Calguarium]

So, there has been a lot of discussion and information about this issue. I 
am presently burning the DVD, might buy another 2 GB of RAM, and am about 
to commence installing the x86_64 version of F11alpha to a spare partition.

Now, I have another question, having arisen out of this discussion (and not 
precluding others that could easily arise, once I have a running system):

As memory requirements for 64-bit are anywhere from 50-100% greater and 
the only appreciable difference is a "psychological" performance boost, what 
REAL benefit is there, actually?