I am not trying to sidetrack this into an Apple/Android debate at all - but I just thought I would add my $0.02 on how I work around this given the limitations of bluetooth with the Leaf. I have a 2015 SV.
I carry an S5 and iphone 24/7. The S5 is my primary phone, iPhone is my work provided cell phone. I also have my iPad Air paired with my Leaf. I have an unlimited data plan on my iPad, so I use it to stream Sirius/XM and Pandora.
The problem is, when I switch over to the iPad - any bluetooth sounds from my S5 would normally not be heard because the bluetooth audio is on my iPad. So to get around this, I use Tasker on my S5 and built some tasks for when I drive that I LOVE and could not commute without. I am unable to do this with my iPhone. When listening to my iPad, I am SOL on hearing anything from my iPhone notifications, unless I turn off the pairing.
For instance. As soon as I turn the car on and my S5 connects to the bluetooth, it changes it from work/silent mode into my version of car mode - full volume for everything, and full screen brightness (depending on time of day of course). This also triggers my driving call and driving text actions. If I get a text, my phone will read aloud the person's name sending the test, and then the text. It will then auto reply to that person that I am driving and I will get back to them once I am at my destination. When I get a call, it says aloud the name of the person calling - as well as being able to see it on the screen in the car. So I mention this because, if I didn't have tasker - none of that would work. It would automatically try to put all those sounds through bluetooth. So I set Tasker to automatically send those sounds through the phone's speaker at full volume. I am easily able to hear it through my pant's pocket over the volume of the radio.
Too bad Apple doesn't have anything like Tasker. I love all the profiles I set up for each of my cars, nighttime/daytime, etc.