Travel insurance needs a whole lot more thought than that and if you don't give it the focus it needs, you'll really be sorry if you find yourself needing to make a claim.
Take chronic medical conditions. If you've got one of these then you'll need to get pre-existing medical travel insurance. This will ensure you are covered should you need to claim as a result of the existing condition. If you were suffering with or previously had cancer for example, or had a chronic stomach ulcer, then regular travel insurance wouldn't provide a payout for any necessary treatment. This could leave you hundreds or even thousands of pounds out of pocket.
Or if you're planning on doing any winter sports while on holiday then you'll need specific insurance for that. Skiing, snowboarding and other similar sports often cause injury. Whilst many travel insurers will provide a small amount of cover, if you broke your leg as a direct result of skiing they definitely wouldn't - unless you had specific winter sports insurance.
Another key situation to consider is whether or not your chosen policy covers you within you're visiting. Say for example you had picked out a wonderful policy that covered all European countries - and you visit New Zealand. Something doesn't add up there! Be sure to pick one that covers specifically the place you are heading to.
These are just a few examples of where choosing the wrong travel insurance can come back and bite you. So be sure to do your research and pick the right policy for you - otherwise you might end up spending more on fixing your problem than you did on the holiday itself!