Why would I want stereo AND mono song version?

I just got the Deluxe edition of Disraeli Gears by Cream.
http://en.wikipedia.org/wiki/Disraeli_Gears

Disk 1 has all the songs in stereo and Disk 2 has all of them in mono. Why would I want both?? It seems more of an annoyance to me to have 2 different versions of the exact same song. I'd rather listen to either the stereo CD or the mono CD. Which ones would be the best bet?

You tell me, you bought it! :D I have the original vinyl. I'll check and see if it was mono. When remastering they might have split it then.

[Addendum]
It states in several places "Stereo playable in Mono". Must have been a big thing. Back then I bet most people would not have owned stereo's. I guess this way they give you the real 60's experience on today's technology.

It's just a matter of taste. Most people wouldn't even tell the difference, but for audiophiles out there it is nice to have the choice. Hope you enjoy it!