... zero clearance table insert are very useful additions to a table saw.
Zero clearance insert is a wonderful thing. Makes nicer cuts, and prevents pieces from dropping into the cabinet. Easy to make for most saws, can buy them for modern ones.
I had a 2 foot long 3 inch wide piece of 1/2" plywood come off the saw backwards at about 300 mph. Put a nice dent in the shop wall 12 feet behind me Missed her head by inches. Happened so fast I wasn't sure what happened until I saw the mangled piece of wood on the floor at the OPPOSITE end of the shop
I had a similar incident, threw a 3" x 3" piece across the shop, dented the back wall. It was an off cut that vibrated into the blade before I could grab it. I keep it in the box with all my accessories (feather board, pushers, hold downs etc) that comes out with each use, to remind me how dangerous it could be. Have to handle it EVERY time I use the saw.
My saw blade inserts are painted red or white, very high contrast to the cast iron. I use them as a reminder to never let my fingers get inside that brightly colored spot.
Whoever said keep your blade 1/4" above the wood has an important point, not mentioned. The blade is then cutting on the downside of the blade, not the top, which is pushing your wood forward, back at you, if you only have a hair visible.
There are lots of great tips on line, but take them all with a huge chunk of salt. If you don't feel comfortable trying it, look for a different way. There are lots of guys out there missing fingers, giving ideas.