I like your idea. I do like this product as my mascara. The slim wand does let you get down to the bottom of your lashes to deposit product on your lashes. It gives definition without bulk and no spider lashes. It doesn't flake or smear. Like Maybelline Lash Discovery, the thin wand lets you coat most of your last almost all the way down to the root. But it doesn't cover the skin at the base of the lashes.
So, it doesn't work as as a tight-line eye liner for me. It doesn't lay down a line of black along the base of my lashes or on the waterline. I use gel liner for that.