What if they don't have a projector, it's not that hard to have your own small/pocket projector; not to mention that you should come with your own battery pack as well, just in case all their fuses break.
Seriously, though…
I care less about the weight as I do the space. In cubic whatevers it isn't much, but if like me you have a classic looking, relatively soft-shelled, briefcase (like
this one) these damn things somehow always end up bulking up next to each other; taking the look from classic, to bloated melon.
My work, and personal preferences, already require me to have things in my bag; and I in no way feel it reasonable that I have to come looking like a traveling cable salesman (or Himalayan backpacker) in preparation for other people to have broken meeting rooms.
I honestly just don't get what kind of sh*t you people are willing to put up with when you are invited to give presentations, and no-one's even bothered to have a functioning room ready for you; and I don't get how you expect a "normal" person to be able to function in such environments.
The average person at MR is probably to be considered a "techie" of at least a junior kind, but these are computers that are used by "normal" people; business people. The equipment has to just work for these people; and like
@senttoschool just showed it's not 100% even someone aware of the problems can quickly just get the right adapter/cable.
I'm sorry, but as much as USB-C
on paper was that one port to rule them all, it just hasn't worked out that way; and it would be best if the ports the computer came with actually supported easy use for most people. If "the market" hasn't been able to get a decent HDMI-port as an add-on, then it's back to the drawing board for Apple to fix this very real problem.