A cursive italic is very similar to a stub in the line it will deliver -- the narrowest portions of an "O" will be at the same 12:00 and 6:00 -- except that the line variation will be a little sharper and crisper, because the edges and corners of an italic are sharper, less rounded. It is still a very good tip for everyday writing, note taking and journal entries although it is not as sharp as a formal italic. Cursive italics do have a small and linear "footprint" or contact area and can be somewhat position-sensitive, especially for people new to customized tips.
If a writer is going too fast, or not paying attention, the pen can be rotated out of position, so the tip will not be on the contact area and it may begin to skip and feel rough. A formal, or calligraphic italic has very sharp edges and corners and is intended for the slow, careful, one-by-one formation of letters. Formal italics are not recommended for daily writing or note taking.