Why do people do this on the market board

[Mykll]

I figure someone could use it, so I throw it up on the market for the default price, or even lower. Especially when I am doing my ventures, if it's something I find worthless, I just go ahead and put it up cheap. I am sure someone needs it.

Exactly what I do. No room on retainer? Vendor then.

Edit:

Especially the mob drop RNG items. It's being nice and letting someone skip that when they only need a few.