I learned the hard way over the holidays that trip interruption insurance is useless.
I was in Paris with a train ride to Frankfurt but the labor strikes canceled my trip and was forced to find emergency trips ASAP. Alternate trips to Frankfurt were full, but thankfully I was able to do a two-leg journey via Brussels which costs more than the initial trip and the CC won't cover it.
Basically, someone needed to be injured or dead for it to be a trip interruption.