Fired employees aren't valued employees. Receiving compensation for someone you don't want and have let go makes no sense, and like I said, it's baffling how they botched the rule.
I don't know how the NHL defines firing, but if a coach is still being paid, they're not so much "fired" as simply relegated to other (probably non-existent) duties within the organization. A fired coach still drawing a salary wouldn't be able to collect (un)employment insurance, for example (ignoring the question whether they are employees or contractors). So if a team is paying a fired coach, the team presumably
should have a right to them as an asset.
Now whether trading NHL currency (in the form of draft picks) is the appropriate mechanism for purchasing that asset is another question, since presumably releasing the team from their financial obligation (which is what I had always assumed happened until now) is probably payment enough. In a free market, though, the teams would simply negotiate whatever agreement they could come to, whether it was nothing, a lump sum of cash, a draft pick, or even a roster player (like the Keenan for Nedved trade!)