I have all lights (100+) in the house on Zigbee but without changing any wiring. Only non standard is that I replaced all the wall switches with a variant that's electrically "always on" and sends a Zigbee command when pressed (and can be pulled out to access a traditional physical switch as a backup in case of full system failure). They fit the original Siemens outer wall plates that my house was built with so everything looks standard. Returning evening to non-smart in case I want to sell the place is an afternoon of work replacing the switches behind the plastic face plate with their old versions. Those are all in a box in the attic :-)
The benefits of smart lights for comfort are pretty big, auto-on lights by motion detection is great for bathrooms, storage rooms etc. Having the color temperature match outside and time of day is also much better than traditional dimmers. Voice control is useful in some situations (mostly when cooking or carrying kids or groceries). And being able to walk out the front door saying "Alexa, turn off all lights" is a great way to save energy and make things easy.