I have an M2 13" air for a personal computer and a 14" pro for work.
The Air is noticeably lighter and much easier to throw in a bag without thinking about managing weight. The Pro is a fine weight for commuting, but for traveling longer distances, the weight definitely makes a difference. To the point where I'm seriously considering setting up a work partition on my personal machine so I don't need to lug the pro around on an upcoming trip.
Probably depends how big and muscular are you. I don't feel 14' PRO in my backpack at all, 16 PRO barely. Its not a flex but it definitely matters if you are a 5'1 female or 6'2 male.
The Air is noticeably lighter and much easier to throw in a bag without thinking about managing weight. The Pro is a fine weight for commuting, but for traveling longer distances, the weight definitely makes a difference. To the point where I'm seriously considering setting up a work partition on my personal machine so I don't need to lug the pro around on an upcoming trip.