I have sewn such damage, but the stitch sticks out and is vulnerable. I have used boots. You get temporary results and have to check the situation repeatedly. In the end, as others said, it is not worth it.
After all that, I have to say that I have one tire, with such a damage, that I simply continue riding. It is a heavy duty studded winter tire. You ride it at such a low pressure that the damage is practically irrelevant as the tube pushes with a weak force against the tire.