Your mainsail doesn't flake. It falls into a messy heap on top of your boom and you hide the mess with your mainsail cover. With or without a Dutchman, many sailors flake their mainsail before covering. The beauty of the Dutchman is that it flakes the sail for you. Add to that that you don't need to tie the intermediate reef points when you reef, there's no lines to snag when raising your sail like with lazy jacks, etc. and the Dutchman is a no brainer.

There are five ways to handle your mainsail- in mast reefing, in boom reefing, lazy jacks, nothing, and the Dutchman sail flaking system. As I said, lazy jacks are better than nothing, but barely.

Disclaimer- I worked for Dutchman and designed sail layouts for sailmakers for a couple of years so I'm biased, but I'm now retired and no longer have any financial interests in Dutchman whatsoever. But I know a good thing when I see it.