If you ever intend to show your car at a concours virtually all require that every car have a working fire extinguisher installed.
This is why I have one in my car. The concours de elegance in my area of California inform us that if we do not have a fire extinguisher, we are not allowed to participate/show the car. Story goes that one year, at some concours de elegance event, a car caught on fire and the flames caught the car next to it on fire.
Interesting thing about having an extinguisher with in arms reach or in visual sight, is that it may make one (usually the driver) feel reassured they have one in the event of a fire. Flip side, passenger may think, is it safe to be in this car if you feel the need to have a fire extinguisher in clear sight and arms reach.
As I mentioned earlier, this topic was brought up here before. I have mine in the boot. Open the boot, quick release to grab it. Topic of it's too far way in the boot etc. My response, is maybe 5-10 seconds more. So depending on where the fire is, engine compartment it may not matter. Or it's in arms reach in the car and it takes 5 seconds to unclip it from behind the seat (should not be just lying there rolling around). Or maybe it's at the front of the seat. Not sure in front of the seat is the best place in case it somehow comes loose and rolls to the pedals.
I carry one as a precaution thinking my car is not going to catch on fire but it's good to have, and I don't need it to be in sight. These cars when new, how many came with dealer installed fire extinguishers in view, in arms reach. How many owners installed one. I've never seen any black and white movies when the cars were new, where there was a extinguisher in the car (not racing movies).
If you truly feel your car is in such condition that it may catch on fire, then you would be a candidate to have it visually within arms reach in front of you on a quick release system. Easy to do on the pre BJ8 cars that don't have the center consul. With consul, maybe under the glove box.
Happy New Year everyone. Drive safe and fire free.