Can you stand, and walk around in it? Like stand up, and turn around without tipping or falling out? Standing is one thing, but standing and fishing comfortably is another. My friend can stand on one leg in a surf ski racing kayak, but that's about it.
Anyway, to the OP, plenty of people fish from a sit in. If it gets you out on the water, then I'm all for it!
It's just that sit on tops are simply better suited for fishing. There's a reason there are 1000 different SOTs for fishing, and about 3 SINKs.
Actually I can and do. It was designed to be both a hunting and fishing kayak. It's wide and 14' long.