Yeah density altitude can be confusing sometimes but as said before it is only to determine how your A/C is/will perform based off of the current temperature and pressure. Pretty much it's just an information number for how the A/C will behave. Can't say I've ever had tower or anyone else ask me my DA in flight. So don't sweat it.
If it helps think of it like this... If your A/C's ceiling is 15000', but your density altitude puts you 2000' above actual altitude then your A/C will actually top out at 13000'. Just numbers I pulled out of thin air but I hope it helps illustrate a performance aspect of DA.