My recent encounter with a couple from Hungary planning to camp across Oahu reminded me of how different camping is in Hawaii from Europe or the mainland. Camping is a popular way to vacation in Europe and beaches are equipped for fairly comfortable family stays. Many of us probably have memories of camping in national parks on the mainland, as well (mine involve a night at the Grand Canyon that was far colder than I thought it would EVER be in Arizona). It is an inexpensive family activity and a good way to get close to nature when campsites are properly equipped.
However, I would not recommend planning to camp for an entire vacation in Hawaii. There are limited campsites run by the city, county or on Oahu. You must apply for the beach permit in person and almost all of the sites are closed for two or three days each week.. In addition to the difficulty of guaranteeing a camping spot for the entire time you plan to spend on the island (and the expense of camping equipment), there are safety concerns. Like any major population center, Hawaii has homeless people and problems with petty theft and break-ins. The safety and quality of life here is far better than other urban centers (Honolulu consistently ranks at or near the bottom on rankings of crime rates) but both homelessness and theft are more pronounced in beach parks. Also, the park bathrooms are adequate for day trips but nothing like the full shower facilities provided at most national parks.
There is no reason to avoid any of the parks, but they are less attractive options as basic lodging than local hotels. That said, camping for a day or two as part of a trip to the neighbor islands might be a fun adventure option during a vacation. This distinction is one of the many excellent reasons to consult with local travel agents when planning your visit.