Most people buy annual family travel policies instead of the expensive and inflexible single trip policy. Many home policies will offer an option for travel insurance, and these are often well worth exploring.
The most common pitfall is a pre existing medical condition invalidating cover, however there are many other potential areas of confusion such as trip length limitations, hazardous activity exclusions, or children’s birthdays at 18 taking them out of cover on an annual policy.
Travel insurance is fundamentally straightforward but as with most things you do get what you pay for.
Cheaper policies may well exclude a range of pre-existing medical conditions and prevent you from claiming. They may well contain very low limits for items such as cameras, and some have age restrictions that might be overlooked.
One of the real concerns with restrictions in any policy bought directly from an insurer, online or otherwise, is that the terms are normal and other insurers would not offer anything different. This is sadly, not the case, for the buyer who relies on the first policy they end up buying. No different in effect to buying a car. Would you buy the first one you saw?