The magnet works like a charm doesn't it. I have thick fumble style fingers and I can't grip anything much smaller than 1/4" reliably.
I'm assuming when you say a metric lift that the adjustment scale is in metric? If you are making a home made jig that needs to adjust and you want to be able to measure the adjustment then using a 3/8" by 16 thread bolt allows that since every full turn moves the jig 1/16". But it's the only SAE bolt with that thread pitch. There are a few different size metric bolts that have 1mm thread pitch which means that every full turn will move the jig 1mm so going metric gives you more options in available sizes.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.