You can use these in place of the tie downs for hard point for a little more security than a tie-down ring. I have a set and they work great, although a 3" piece of 3/8" all-thread with a nut to secure it will work too if you're on the cheap...
I use the tie down points as jack points as recommended by Vans. I insert a 3/8? carriage bolt in the hole and modified a HF jack as shown here. It?s pretty simple, certainly cheap, and allows some movement at the junction of the bolt and the jack. BTW, the same carriage bolts are used on jack supports providing some nice feet to slide around the concrete floor and to keep the wood from getting soaked from any water on the floor.
Another builder showed me his jack technique and then I built a similar setup to his. Take a 3 ton HF jack (https://www.harborfreight.com/3-ton-super-heavy-duty-long-ram-hydraulic-flat-bottom-jack-36468.html) and put a floating 2x6 top on it, 2x6 base, and a stick of conduit for the braces. The 2x6 top is sitting directly on top of the jack but has a steel ring screwed to the wood that goes around the jack to ensure the wood does not walk yet can adjust to the angle of the wing. Put a scrap alum plate under where the jack will impact the wood to ensure the point load is distributed on the wood. The wood is covered with carpet to keep from scratching the paint. Jack is placed so that the jack post is centered on the spar and the inboard end of the 2x6 is outboard of the fuel tank. Works really well and very little chance of punching a new hole in the bottom wing skin. Total cost for the jack was around $60 with the wood etc.
I tried the Anti-Splat but I like the Bogert jack points MUCH BETTER - they include a fitting that forms the cup for the ball of the wing fitting, so there is little chance of the jack slipping. The "cup fitting" fits perfectly on the ram jack. If I am going to do much work on the airplane I put padded sawhorses under strong points on fuse (firewall area, bulkhead).
Another variation on the tie-down location for jack points. I made these up on the lathe in a few minutes. The taper angle is 90 degrees. The taper fits into the recess on top of the HF jack ram. I made the recess using the large countersink cutter that was used for the seatbelt anchor in the -10 canopy. That results in a countersink angle of 100 degrees, so there's 5 degrees of tilt in any direction for security while the plane is jacked up.
Another consideration for those still building - rivet a shim in between the skin and the the threaded extrusion tie-down point for jacking, so that the weight isn't supported by just the thread on the screwed in fitting...