The wife has ridden her cheap ebike every day since summer, with the only actual waterproofing done with some electricans tape around the controller box. Its going inside at home, but at her work it stayed outside. After 6 months it gave up and the damage was the batterys power checker, and the control panel. don't know what gave up first.
The bike was "professional" built by a Norwegian shop, so I assumed that it would hold up in Norwegian weather. guess not.
Now I built her new bike with BBS02 motor, and althou the connectors all look good, i put some good grease in every open hole, doesn't take much and gives me peace of mind.
I also have a ebay 500w front hub motor kit, and no way thats made to be waterproof, I'll change all the connectors to proper waterproof ones and waterproof the rest of the system with grease. thick grease does a decent job at waterproofing electrical components...
Anything that can't be used in the rain is for indoor use only, and I don't have a house big enough for a indoor bicycle...
You don't see many capes around here, they probably work ok if the rain comes from heaven straight down, but around here its always windy, so its waterproof trousers and coat, or get wet. Me myself, I grew up here, so I've adapted to just be wet, and thats ok, I don't care.