Don't forget you also need a longer chain with a derailleur too. Those links aren't light weight. You also have shorter spokes on an internal hub and it tends to be a very strong hub as well. Also your weight is incorrect for the 8R25 aka redlabel (high efficiency according to Shimano). It is actually 1550grams.

One other big benefit on small wheeled bikes that nobody seems to use, is the option of going with a roller brake. This makes a lot of sense given the accelerated rim wear I've seen on some of my bikes and especially the Bromptons. These small rims are definitely eroded more quickly by the brakes due to the fact they turn more rpms and have less swept area.

I am not saying there isn't a weight disadvantage with the internal hubs as there is. I do love their benefits on a folder. Nothing hanging down to get all over your pant leg. I can shift at a stop. No low chain that sucks in dirt and debris. Very quiet gear changes. The Shimano shifts great under load. I could go on and on. A pound or so weight penalty isn't going to kill me. It is a folder, not a race bike. I can lose the pound in a day if I want.