To buy or to rent, that is the question...
I can only speculate, since I don''t know the company and have not seen the agreement but...
That seems like a terrific responsibility on their part. But I think the fine print would most likely be: they are NOT responsible for ''normal wear and tear'' (hard to interpret), cosmetic damage (like chips cracks and crazing of your gelcoat, which really can devalue not to mention delaminate your boat over time), etc.
Also, my charter co demanded that *I* insure the boat for charter (AND list them as co-insured for personal and property damages). SO, if we assume the same for your instance, I would guess that their end would be the deductable. Of course, with claims your insurance costs will go up.
Just a guess.
Still, many people go the charter route. It IS a way to greatly limit costs. I think the two more successful instances of this are 1) people who buy new via a program in the Islands where charter is lucrative and they only use the boat a couple times a year, can appreciate the favorable tax benefit of depreciating the boat and then dump it after 10 yrs or 2) people who own older larger less expensive boats like O''Day''s that have depreciated to nearly nothing and they stick them in charter broker fleets because they will not be using the boat again or just rarely and don''t care what happens to it.
Just my opinion.
Of course the other way to go is to simply get a much older boat (maybe a classic) with an initial low cost. It is possible to find some that have been well cared for, not easy, but possible. You will likely not get the great condo like interior of a modern boat, but your cost is very very low. For example, you could get a Catalina 34 or 36 (you said you were looking at these), mid 1980''s vintage for around $50k. The mid 1980''s C''s were built pretty well and hold their value. You could use the boat for 5 yrs and get what you paid. You could also dump it into a charter fleet if you moved and possibly gain some income.