Just discovered your Grid Builder. Maybe it is a lack of understanding on my side:
Wouldn’t it make sense, one can choose to fill the grid applied initially with div’s for its items, because this might be the 95% use case (not sure that that is the case)?
I don’t think there should be any presumption of what the grid children should be. I would agree that it’s most likely going to be a Div, but a lot of grids are built using query loops, which only require a single element that gets looped. Also, if you build a grid of “cards”, for example, you’re likely going to design a single card first (or component) in one Div and then duplicate that Div/component however many times you need for your grid. These are only a couple of reasons off the top of my head, but my preference would be that it DOES NOT auto add grid child elements.