Doing "upgrades"

[Licensed to kill]

There are certain "upgrades" that some people do to their otherwise stock model A's that puzzle me so I thought i would ask. This is partly in response to the thread on "grease" where the discussion involved original style vs modern grease nipples. My car has some of each and was missing a couple when i got it so I replaces the missing ones with original style. I have an original grease gun that came with another of my model A's so I use that on those style nipples. Yes i need two different guns to grease the car but that is a non-issue for me. Curious as to why someone would change out all the original style in favour of modern nipples?. Another curiosity is when someone converts their otherwise stock Model A to 12V and sometimes neg ground. I rather like all the charming features of the car and the 6V positive system is one of them. The only reason that I can think of is availability of parts should you break down on the road. However, there is SO few electrical things on the car that, should i go on an extended road trip (which I intend to do) I can just carry a few spares and the only one that comes to mind (other than perhaps a couple light bulbs) is the generator and an ignition coil and condenser. Not much else that I can think of that will cause grief. I can start it easy enough without the starter should that fail. I guess what I am getting at is, since i am new to these stock model A's, is there something I am overlooking?. Is there a reason why a system that worked well for decades should be considered "upgraded" today?. I hate to lose the charm of these old cars unless there is a practical reason.