I carry my backpack as a summit pack also, which saves the weight of carrying a smaller pack. Three nice things about taking the backpack with me:
I can take any of my gear needed since it already fit into the backpack size is not a problem.
It keeps my $800 pack close to me where its safer.
The pack is modular and can be from 29 ounces up to about 54 oz with all of the pockets, shovel holders and gadgets attached so I could simply remove the pockets, stiffener, etc and leave them in my tent. Backpack makers have been loath to produce modular packs since then people might only have one backpack, like me essentially. I do have an ancient Kelty Tioga external frame to loan friends. (and ok yeh I have 6 or more little packs including a Ray Way pack, but I don't ever carry them)
This was perhaps the final idea/use that made me pay $500 in 1988 for a Kelty White Cloud. A few years ago the water proofing started coming off the spectra so they sent me a new Cloud 6500. Nice people at Kelty.
Jim