Commercial operations only sell shiny bullets, because people won't pay as much for frosty bullets.
Functionally, they are the same.**
Hot molds give you frosty bullets. If it works for you, don't worry about it.
If you want shiny bullets, slow down a bit, or see if turning the melt temp down a hair will help.
Almost all of my bullets drop out frosty. It's caused by my casting tempo. Once I get moving, it is hard for me to slow down. So, having to wait longer between pours, for the mold to cool down, doesn't work very well. I'd rather push as fast as the mold will allow me (without overheating), and shoot frosty bullets, than wait longer between pours, just so they look better.
** If some one wanted to be picky, they could get into a discussion about minor bullet variations caused by alloy and mold temperature, such as shrink rates, densities, dendrite formation, etc. But, if your methods are consistent, the bullets will be close enough that it won't matter.