Im a newbie to snowboarding, Silly qs but Im wondering if you could wear your ski boots and ride a snowboard comfortably?
Welcome to Epic!
There is a type of snowboard binding that does work with ski boots. Typically these bindings are used on what are called "Alpine boards" and are set at "forward" stance angles. Alpine boards are designed for carving on groomers, they don't do tricks or go backwards very well (but some riders do that just fine thank you). The reference stance angle for snowboarding is called zero zero (where your feet are mounted 90 degrees/sideways to the length of the board. The old fashioned stance angles were the front foot angled 5-15 degrees forward (a plus number) and the back foot angled 0-5 degrees forward. The current fashion stance is called duck (for duck foot) where the back foot is angled 5-15 degrees to the back (a minus number). Alpine stances typically are more forward (front foot +20-50, back foot >15). The movements for alpine riding are significantly different (e.g. more leaning side to side) than regular snowboarding. There are snowboard specific hard boots that are designed for alpine bindings. These boots are softer than regular ski boots, but still much stiffer than regular soft snowboard boots.
If you try to ride a snowboard with ski boots in a regular stance (vs an alpine stance), you're going to be in a world of hurt. First off you won't be able to make the movements needed to make the board turn. Secondly, you will have binding issues. A ski boot won't fit properly into a regular strap binding. And an alpine binding will hang over the edges and catch in the snow if mounted "sideways".
Been there done that. It works. But ski boots are noticeably stiffer than hard snowboard boots. If you're going to make a habit of riding an alpine style snowboard, you'll want to invest in snowboard specific hard boots.