I use leaf mold as a mulch and soil amendment (I don't till it in). In my
experience all my vegetables like growing in beds mulched by leaf mold. If I could make more of it I might switch exclusively to mulching with leaf mold instead of that and
wood chips.
But it does get blown around more easily if it's not broken down fully into duff. And birds like to kick it around. Once it's truly broken down into dark duff then it stays put better.
Leaf mold is made by fungi slowly breaking down leaves so plants that like fungal based soils will like it more. Brassicas like broccoli tend to prefer more bacterial dominated soils so regular
compost might be better for those. But I use leaf mold for all my vegetables and they seem to be happy with it.
I put leaf mold down in the fall and let it sit over the fall and winter so it continues to breakdown over that time. It really is a great mulch and soil amendment. Worms and other soil life love it too!
I haven't yet grown sweet potatoes but my guess is they would do really well with leaf mold.