I've been riding fix gears with axles sticking out on the road forever and never seen a need. Any minor damage to threads is quickly straightened out backing off the nut and I have never managed to scrape my leg on it. It looks like just one more thing to have to deal with every flat tire. That axle adjust too!

Trick to getting chain slack very close first try - slide the wheel back firmly against the chain with your left hand at the chainstay, pulling the tire against the chainstay, While holding that firmly, semi-tighten the right (DS) hub nut just tight enough to not slip. Center the tire between the chainstays. Tighten the left (NDS) hub nut. Check chain slack. (I use the wrench and just look for about 1/2" of slack. Spin the pedals and see if the chain goes too tight or loose.) If the chain passes that test, I tighten the DS nut. Done. And next flat, no axle adjust to deal with!

Very strong track riders were using just hub nuts to secure the rear wheel for a century before this fad of adjusters. (They are useful it you want a really tight chain but we old-timers know our drive trains run better and last longer with proper chain slack. If you go to a velodrome, you will see that slack on the vast majority of the bikes and on all ridden by the hotshots. Good mechanics know.)

I realize taking my advice means removing stuff that looks elegant and that you paid for. Reducing the image of the bike from shiny new to a useful working tool.