55 pounds – not exactly lightweight, but still light enough for most able-bodied folks to carry up and down a flight of stairs.
Riiiight. Try lugging 55lbs of awkwardly shaped steel up a narrow staircase. And pray that it's completely clean when you're doing it, and that you aren't carrying anything else with you (a bag, purse, backpack, panniers, etc.)
Folding ebikes are only convenient when they are in storage, not for lugging up stairs.
Who is this for? A $3k bike that I bring with me everywhere - where it could be stolen? I'm American though so bike security and taking bikes on busses/trains is a limited luxury, bike parking is completely nonexistent.