Obviously it does not literally add 1/10 of a dimension. However, saying "2.1 dimensional" gives people the idea of "oh, it is still mostly the same as a 2 dime

Obviously it does not literally add 1/10 of a dimension. However, saying "2.1 dimensional" gives people the idea of "oh, it is still mostly the same as a 2 dimensional thing, but is a little bit closer (in some sense) to being 3 dimensional.".