Yup. There are two types of radios in the bands.
- RFID is a passive technology (no battery) that is used for park admission, fastpass, room access, payments, etc.. That technology requires the band to be essentially in contact with the active reader to work. because the power is in the reader and it covers a very short distance.
- The other is Bluetooth LE (Low Energy) which is the active radio that uses the battery. This is used for some of the more passive activities like on-ride photos. It's also used by Disney in an anonomized way to monitor crowd patterns flowing through attractions. It's also the tech that is being introduced to measure actual wait times without the older red card system as a guest moves through the line. There were a lot of other things they hoped to do early on but privacy concerns and other operational issues/concerns pushed those to the back burner.
The battery in a Magic Band will eventually wear out in ~3 years and when that happens the proximity things like on-ride photos stop, but the active contact things like room access, park admission etc keep working because the power for that is in the reader, not the band. So you could theoretically use any MB forever as long as you understand that the passive functions would stop working somewhere around 3 years after activation.