Can someone tell me the pros and cons of a one-compartment hiking/mountaineering backpack?

I’ve recently come across this one (pic related): EXPED Mountain Pro 40 M

I love the design, but it’s got one major flaw - no outside compartments for bottles. In fact, the backpack only has one main compartment and the another small one in the pack lid.

Is the normal now? Am I supposed to take off the backpack and open it every time I want to drink a bit of water?