The issue isn't really the boat, it's of a reasonable size (70m) and has pretty much everything it needs. The intention isn't for long trips. Will be <6 hrs mostly.
The real question is how safe are the Billy Pugh transfers, I have done many and haven't had an issue (you are supposed to connect the lanyard to your PFD although this is often omitted in briefs). But, is definitely a risk of injury during the landing of the basket, particularly when there is movement on the deck of the ship. I suspect the limits if the Billy Pugh are less then helicopter transfers. Cost difference I can't imagine will be vastly different overall. In certain countries the cost of seafarers is so rapidly exceeding helicopter crew that it's vastly cheaper to use a helicopter even with all other costs involved (example pilot embarkation in Australia).