I actually went 5V and it’s fine. I forgot to stress that in the post but I’ll update it.

5V is extremely bad from efficiency point of view. The voltage drop over an LED is ~3V, that leaves 2V to be sent through the current limiting resistor (dissipated as heat). There could be only a single LED (no series).

These strips have a chip and individual control for each RGB LED that work on 6V max, so "higher voltage would be better" doesn't really make sense for them (unlike strips where all LEDs in the strip are driven the same, without individual control).

Obviously, I didn't mean addressable RGB LEDs, just regular LED (white) strips that can be cut (in the context of the grandparent's comment)

I considered using 24V for my living room lighting, but availability is an issue. The much more common 12V works fine as long as you consider the wire gauge you need to prevent the voltage from dropping too much.

For example, if you use RGBWW strips (i.e., four channels; RGB plus warm-white, as you rightly recommend), you could have one -12V lead shared with a thickness of 4mm², and four separate 12V leads at 1.5mm². At around 4.2m distance (at the farthest) I measured an acceptable voltage drop of 3.9% for 405 SMD5050 RGBWW LEDs.

But yeah, you do need to consider the wire gauge of your cabling, depending on the number of LEDs driven.

Why 24V? What does it improve?

Power is proportional to the voltage squared (P = V * V /R), so the power supplies need less current -- cheaper, more reliable - less heat, less voltage drop.

The same holds true for the power supply in NA vs most of the world (save Japan). 110V vs 230V - much less copper needed for conductors. motor windings, etc.

Flip note: the better option is using constant current drivers, for higher efficiency (they might have unsafe voltages, though)

More light output mainly. If you have a look at the philips hue lightstrips you'll see it there too. The 24v pumps out way more lumens. i.e. Useful levels of light not just decorations.