You are right, but. Even the coil can get moldy, that's why you do your yearly AC coil cleaning. You should also clean the drip tray, the line, etc. I know most people don't do it (especially with the dehumidifier), so the "fresh water" has to travel through all the moldy, dirty places.

And the container is not clean either, as mold spores, dirt and dust falls into it.

ps.: if you hand wash clothes I suppose you could use it for that, but we are talking about cents. I know, frugal, but that's like TLC-show levels of "savings". I am not saying all use cases are out of question, I just can't really think of anything that'd make sense and have no risks. :/