Of course you can use them on handguns, but, you will suffer the same problems.
Is there a benefit over traditional open sights? Quite possibly on handguns yes. Rifles, a matter of opinion. Are they as good as traditional aperatures on rifles, in my opinion, absolutely not.
I am offering my opinion, based on over thirty years of target shooting, and hunting with mainly aperature sighted rifles. You are welcome to yours.
Posting new products is great, but we should all be able to express our views on the product with out worry of offending the poster. There are a lot of new shooters here that can benefit from the discussion.
It is a fact that when an aperature is held close to the eye, the eye automatically centers in it, allowing the shooter to focus only on the target, and front post. Further, vision improves.
Try reading fine print through a pin hole punched in a piece of paper to see the effect. Both these effects are lost when the apperature is moved away.