Seems they are flogging registrations via a company. Nothing wrong with that, just adds cost and complexity / aggro (whether simply on the annual company paperwork or by complicating personal tax affairs).
As a broad ballpark would be lucky to get away with an "offshore" company (BVI / Delaware / Cayman etc) costing USD1k a year (in Govt fees
and local agent / registed office costs) and in practice likely USD1500 plus (set up cost IRO USD1k). For a Jersey one you can double all that!, and only that "low" if it does SFA
My order of preference would be:-
1) Reg in own name in "home" country
(and suck up any PITA rules and costs).
2) Reg in own name "offshore"
(if you can meet any passport requirements, i.e. EU or Commonwealth citizenship for a Jersey reg).
3) Reg in a company name
(offshore or onshore) only if you really really
need to (say because you don't meet the residency requirements for your home country and have the wrong passport for your current
location, or for a personal offshore
boat reg) or you actually understand why it will
save you money
(even when the taxman knows!) or you simply value privacy / conveniance (some people do have enuf money
not to bother with paperwork themselves - "paperwork is for the little people"
I am surprised that no one has summarised the bones of the requirements / ballpark costs / pros and cons of the various common boat reg jurisdictions - well, I couldn't find anything
(seems that most of the info is provided only on what folks are selling).