I want to give a little clarification on my post.
A few years ago I decided to consolidate my firearms "collection" with an emphasis on logistical issues. I sold off most of what I owned and migrated to 9mm Glocks, specifically a 19 and recently this 26.
9mm so I'm only stocking one relatively cheap caliber. Glock 19/26 specifically because both will take a 19 magazine if necessary. The fact that Glock magazines are cheaper than other types isn't a deal breaker but it IS a consideration.
As a couple other people have mentioned ammunition is cheaper in bulk so it only makes sense to me to by a case of SD ammunition rather than a box here and a box there. So ultimately all three Glocks will be loaded with 124Gr.+ Gold Dots. (Actually they all are now)
It just happened that this particular purchase was an impulse buy. I mean I already planned on getting a 26 but I was thinking a little further down the road. Normally I would have already had some Gold Dot on hand. But since I didn't I had to buy a box. That's what got me thinking.