I was aware of the website purchase, but without shipping, it is no more than a reservation.
Microcenter limits the bundles just like all others. Limit 1 per customer per 2 weeks, as explained to me by the general manager. I've bought several of the 2600K + $80 off motherboard bundle, but I have to wait 2 weeks between.
As nanaki333 said; the whole point is, it costs me $24 in gas and way more than $100 in my time for me to go to Microcenter, so it is cheaper for me to order from Newegg most of the time, however, when I am in Atlanta already for business or on a family trip, I do stop by the store as a general rule if there is a major deal going.
Here is the catch, and why their deals work for them: most of the time, when I go in, I end up buying an additional item (or three), and that is the reason they run the deal in the first place. In-store pickup, getting you to the store with a loss-leader, then selling you more. At least I get them to price-match Newegg so I still win. And as far as I know, Microcenter is only in very highly populated metropolitan areas.