Welcome to FT!

This is technically against the airline rules (JDiver seems to know where all this info is hidden and will surely add the exact text). It's called "hidden city", I believe- the idea that you buy a cheaper flight that goes further, then get off. may not be the realy reason, but the rule protects against that. They could deny FF miles, or charge a higher fare, if appropriate. Reality? Since it's the last leg and you don't seem to be a repeat offender...very unlikely to have any impact.

Cheers.