As I understand it, the ham while climbing the mountain to check their remote site, does not want to get there only to discover dead batteries. The mountain top ham shack does not have lights and they need more than a 90 second backlight timer. The mechanical movement is bullet proof (except the ones now made in China). They survive the worse conditions known to man for many decades. There's no way that delicate electronic head will be as robust. And what about all that sun light at the top of the mountain? Is it sun light readable? While the hams love to mod their Birds to add peak detect circuits and play for hours adjusting the pots to get the movement to work just the way they want, this kit missed out. Really, what you want is an electronic measurement circuit that drives a stepper motor meter, like what's in your vehicle.
Of course the biggest problem is for the CBer. Saying your 100W amp is able to put out 102W and then based on this meter would get you in a bar fight.
Not many hams have remote sites, but commercial two way radio & pager services did, & may still do.
A Bird sitting inline between the TX output & the transmission line is a very useful indication of correct operation.
Marking the meter scale at the reading coinciding with the correct output power, as determined by better equipment during installation was a trick often used commercially.
That way, it doesn't much matter if the Bird is reading a bit high or low, it is still a good indicator of correct power level.
The hams who look after repeaters, beacons , & the like, are most often employed in the RF field, & have loan access to much more sophisticated equipment than Birds to set the place up to "spec".
By the way, "remote sites" are normally buildings of some kind,--in the ham case, usually reasonably well constructed metal sheds.
LED lighting is cheap & economical, as you need a solar panel & batteries to run the equipment, in any case.
Of course, if the electricity company has run power up the mountain, "all bets are off"!
In the quite different case of a ham sitting open to the elements on a "bare" (blunt) mountain peak, chasing "peaks on the air" contacts, I very much doubt that anyone would take a Bird, original, or modified with them, as they are additional weight, but they may take an El Cheapo SWR meter, or a Nano VNA to check the antenna.
Some others, may simply rely upon the inbuilt VSWR/power meter in the transciever.