Do your own risk assessment.

1. What's the worst possible impact if you don't have a liferaft?

2. What's the likelihood of you having to use it?

3. Does the cost outweigh the worst possible impact above?

AND if you haven't done it then do do the sea survival 1 day course!!!

My answers:
1 .You, and others whose saftey is in your hands, die
2. Unless your answer is "never" then answer to no 1. over-rides your answer
3. What price do you put on life?