Although I wear Flyfishing vestpacks, with front pockets and integrated rucksack, I happily put up with the chest pockets as tolerable for usefulness for small stuff when fishing.
I keep a chest pack in car with a rod for impromptu ultra light fly fishing on my travels but often wear it sideways when walking to\from fishing as don't like object bouncing against my chest.
With a rucksack, I much prefer just on my back (I cut off\ remove chest straps as I find them restrictive).
However, all my rucksacks either come with or I customise dump straps, so it is easy to dismount, so never an issue to take off and put back on.