Nice unit - no doubt.
Essentially a combination unit that is charger, emergency start - so it apparently contains a battery, and some line switching capability.
By all means, if you like it go for it.
Or if you have multiple batteries in the boat and jumper cables, you can do essentially the same thing for the bulk of the applications.
But, if you like it - I expect that it will do a nice job for you and your boat and power needs.