I disagree, it's a different system here an does not need to perfectly replicate NHL rules. Here, when a guy is given a 1-way deal he is being guaranteed his full salary and top-team play time. However, if he is doing horribly, or to expensive for a team he can be placed on waivers for others so that he may continue with others with his negotiated deal. Or else if your waiver slots are full, you can buy him out whenever. Also, if 1-way deal just had to wait out waivers for a couple days and then be able to get sent down, it would also enable hoarding of better players which has been an issue in the past.
Waivers are there to give you an out to 3 horrible contracts at a time. Whether you signed those deals yourself, or else a previous manager, it opens up salary so that you aren't locked and forced to control a bad team for a number of seasons.