Digital BW, The Print

This question is going to show how little I actually understand 
ColorSync, even after all this time. Maybe Carolyn can set me 
straight.

I just had a new custom profile done with Gen4 and ESFA. This 
is the procedure that I followed before printing all the color chips:

1. Printed Dan Culbertson's BlackRamp to determine best 
MediaType. (I chose "Photo Paper").
2. Set up Photoshop ColorSettings according to ProfileCity's 
instructional PDF.
3. Then, output the chips for profiling, as normal.

But in #2, the ProfileCity part, the PDF instructs you to set your 
RGB Working Space to your monitor profile. In my case, after 
running Optical and calibrating my Pressview, the file is called 
"Monitor RGB - Radius 21SR Profile". You're also to set all of 
your Color Management Policies to "Off".

What is the real-world difference between setting your RGB 
Working Space to your Monitor Profile, rather than, say, 
Adobe98? After I think about it for a while, I'd think that I'd 
ALWAYS want my RGB working space as my monitor profile, 
because I work "from my eyes", as in I judge color mostly from 
the monitor representation, rather than by the Info Pallette.

Maybe I'm making this all too hard, but I'll be darn if I can really 
"get" ColorSync. If someone explains it to me, I'll shake my head, 
and say Yes, but I couldnt' really explain it to a third person. 
(Don't tell anybody).

Any simple-English answers very much appreciated.

-Mark Tucker, Dunce

PS. The ProfileCity PDF is here for download:
http://marktucker.com/epson/profilecity.pdf
.