That parameter helps me greatly with either Xorg or xfbdev, but I might be a special case..
Even though I use high resolution monitors, I very rarely run at anything higher than 1024x768 - and frequently use 800x600 (or anything similarly small with my raspberry Pi's).
At these small resolutions, the video delay / stuttering is very noticeable - especially so with terminals full of text. I don't do multimedia on my *core installs, but mostly shell stuff, so I don't need full resolution anyway.
Also part of the reason for the small resolutions is that I really dig the whole flwm/fltk thing. I have to run a small resolution to make them comfortably large enough for me to use. I like all the utilities..
You might be able to see what I'm doing - boot with vga=ask, and run with say 800x600 on your monitor. Pull up aterm, xterm, fill it with text like dmesg, top etc.
Now drag it around, or do a resize with CTRL-ALT-M. Now perform the same test with the video=vesafb:ywrap,mtrr:3 option. At large native resolutions you may not notice anything. But at my fltk/flwm-lovin' resolutions, its a bit distracting.
None of this is a show-stopper for me. Just stuff I noticed.