1. As a young child these shows are what inspired me to study and investigate, so in my opinion these shows encourage the scientists of the future.
2. Its always cool to see amazing images of erupting volcanoes.
3. These shows are very good at explaining things so that everybody can understand them.
Among other reasons!
It has also been refreshing to see shows which not only just focus on the eruptions themselves but human interest stories and looking at how volcanic eruptions effect the natural environment and animals which get caught up in them. For example I watched a recent show based solely on Octopuses (Octopi?) around Stromboli and how they have learnt/adapted to the hazard of falling blocks from eruptions. Despite the very cheesy opening sequence involving some form of leopard/cheetah jumping into a lava dome that then erupts with Hawaiian 'runny' (or low viscosity) lava, a series of programmes called "Life on Fire" has had some very good filming and fascinating looks at the animals which live around the volcanoes, such as birds who use hot ashed to hatch eggs and the effects of erupting Alaskan volcanoes on Salmon.
Having said this, I do take some exception to some movies, most of them on the budget movie channels, not to be named here but show things with ridiculous titles such as 'Monster Shark vs Giant Octopus' (Syfy channel...cough cough). I have unfortunately had the opportunity to stumble across a couple awful volcano related films. Saying this there are some good dramas, such as the BBC Docudrama 'Supervolcano'.
If you have any comments or disagree in any way, please comment, I am always up for a healthy debate (Keep it clean please).