Wax sits on top of your paint like a sticker, and it's gone in a couple of months. Ceramic is different — the SiO₂ polymer flows into the microscopic texture of your clear coat and bonds to it chemically. If you want the chemistry and the arithmetic side by side, we have written up how long wax, sealant and ceramic each actually last on Calgary roads.
Once it cures, you've got a semi-permanent layer that's harder and far slicker than bare clear coat — a new sacrificial surface that takes the UV, the salt, and the wash marring so your actual paint doesn't. That word cures is doing more work than most people realise, and it's worth knowing how long the cure actually takes once you drive away before you pick a date on the calendar.
That's the honest pitch: it's not a force field, and it won't stop gravel. What it does is lock in your paint's condition and make the car dramatically easier to keep clean.