Some of those ocean kayaks don't have footwells wide enough to have any kind of shoes on. My Kaskazi Dorado is that way.
I wear waders with foot stockings but no way I'd ever go completely barefooted fishing salt water. Carry a pair of crocs as well in case I get stranded and have to walk out. I've worn lace up boots with seal skinz socks to keep feet dry. Had a kingfish in the kayak one time that was gnashing its teeth.. I had water shoes on but don't even think it would have helped if it had bitten my foot. Only takes one bad experience to make people reconsider their choices. Don't want to step on a ray in the shallows from what I've seen. Its hard enough to keep hooks out of my 10 fingers much less toes. Lots of portuguese man of wars with tentacles ... sometimes it will wrap on your line and you won't even notice it until you grab your line to clean it off and you will be in stinging pain. I always wear gloves too.
Once had shark bite my live bait, one foot from rod tip. Was freelining the bait for snook, see a tarpon, quickly reel in live bait and leaving it dangling from rod tip with rod across deck, just under the surface so it wouldn't die.. grabbed my tarpon rod and cast at tarpon with topwater..Boom, shark hits bait right next to bow of kayak, almost dumping me, grab rod as its about to get pulled overboard, drag screaming.. reel in topwater with both rods in my arms. Fight shark for half an hour before dragging it to shore.
this was the guy that did it.. first shark I'd ever caught from kayak and it was a "silky" ... skin just like a trout. Had 3 or 4 other hooks in it where It had either bit through leader or someone had cut it loose.
No, I won't hang my feet over the kayak into salt water.