Is nirvana just the end of a causal series?

It is often said that nirvana is bliss. What I'm struggling with, and have been for years now, despite reading a fair amount, is whether nirvana, being blissful, is not just objectively so. i.e. is nirvana good for the buddha or saint that achieves it? Because if it is, then I don't think it can *only* be an end to the causal series. Just like, when a fire has stopped burning, we don't say the fire is not hot.