Ham Radio is a hobby. Most of us do it for fun. It is a significant investment both financially and in personal effort to be involved in the hobby. You must be licensed. To be licensed you must pass some tests.
The radios allow us to connect and communicate over the air in many different ways. Distance of communication is virtually unlimited.
Many ham radio operators use their skills and radios to pass emergency information. This is being done right now for many of the hard hit hurricane places. The messages are usually about health and well being and sometimes can connect the remote party to a relative when phones and internet are down.
These radios, specifically, are "software defined radios" which means basically they use a combination of firmware and software to make the radio work. The benefit of these over some other types of radios are many fold but mostly they can be easily updated and offer enhanced abilities like the ability to visually see the radio spectrum on your display which allows you to find signals.