It's true. There are no channels in the old sense. Rather, the radio uses a wide range of frequencies and spreads the information across them. Here's an explanation of how it works.
In practical terms, 2.4 is a big improvement over the previous FM systems. Most importantly, no more risk of being shot down by someone on your frequency. No long cumbersome antennas. No problems with electrical noise. Much better resistance to other kinds of interference. And radios are much cheaper and more capable.
On the other side, you do need to understand that 2.4 signals can be blocked by conductive stuff like aluminum, engines, batteries, CF, etc. and how the receiver should be chosen and installed for a particular type of model. Not difficult but different.
You also need to understand that, with certain exceptions, receivers are not interchangeable between systems. A Spektrum receiver (or clone) works only with Spektrum transmitters (or compatibles). Same for Futaba, etc.
You have some reading to do, but it's not so hard. When you have specific questions there are lots of people to offer advice (!)