They are a sign that the wearer wants attention but otherwise are neithe more or less formal than a four in hand. A wool challis is less formal, as is a wool challis fih, and a midnight blue satin is more formal, just alike a midnight blue fih.
There have been several "standard" widths the past fifty years. 3 1/2" perhaps has had the most run but 2 7/8" was the width for quite a while in the 70s and 80s (assuming I have my decades right) while 3.75 to 4" was the wide standard until just a few years ago.
I use a good Braun electric during the week and it gives me a better shave than the barber I go to who uses a straight razor. That said, I DE wet shave on weekends because it's a luxury. The electric doesn't compare.