I run my business from an X1 Carbon, but it's more about portability than battery life. Trains, planes, Starbucks all have power available so it's constantly plugged in and I can't remember the last time I used it on battery for more than an hour.
So, to address your question (which I would normally also ask), it is that important though this is also a somewhat narrow use case.
They also run very cool and are effectively silent even when the fan DOES eventually turn on for a sustained max load. By comparison, every Windows/Intel laptop I've had over the last decade exhibited obvious fan noise every time there was some short-lived load on the CPU - that includes several nicer business/pro grade laptops including Dell XPS, Latitudes, and a Thinkpad.
...and NONE of those other laptops came remotely close to reliably lasting 10+ hours on battery like the MBPs can/do.
Battery life matters. Maybe not to you, but it matters.
Even on trains, one must be lucky and even if lucky, it is usually one socket per pair of seats.