I currently drive a BMW and I use them. But that's because BMW driver is a state of mind and not based on the car you own. I am a Toyota driver at heart.
The state I currently live, Louisiana, and it seems like blinkers at all is a premium package upgrade. Hell, half the time cops don't even use them around here. The only vehicle I can reliably see use them are out of state 18 wheelers.
Was behind a driver's Ed car once, no kids, the instructor. No blinker used....
My brother once gave me a ride home from work, back before I could drive.
He had a Mercedes. Not only was he drinking beer while driving, he refused to use his indicators/blinkers
When I asked him why he didn't signal to other drivers, he said with a smirk
"They didn't come with this model" and proceeded to finish his can of beer.
Ah this again.. BMW offers an indicator subscription.. you get 10 free flashes per month, and then if you haven't bought in, it's pay per flash.. sheesh.. how is that hard to understand? ¯\_(ツ)_/¯