Active speakers have an amplifier built-in and work great as a single zone solution, they just need to be connected to a mains power supply and can be controlled from your device using either WiFi or Bluetooth. If you are only looking to install ceiling speakers in your bathroom then these are a great, cost-effective option.
Passive speakers require an external amplifier to power them over speaker cable. This is the best option as part of a whole-house audio system, and amplifiers from brands like Sonos, Denon HEOS and Bluesound allow you to choose which rooms are playing audio straight from your device. Passive speakers are also often able to offer a better level of performance.