In this one particular case the plug has to go through a side hole due to a narrow and shallow soffit, without interior access and due to the location I'd either need a 15 foot drill bit to go through every rafter tail to run the cable. Or tear the soffit apart which is nailed together very very solidly. That's why I'm reluctantly going to run a surface wire similar to how you get retrofit cable/sat/tel installed by the utility. Exterior rated cable came in today. Fortunately it is only a short exterior run on the least accessed side of the house, and I'll paint the wire to match the trim.
I like the metal boxes. They paint reasonably well too. Our local box stores have gotten into the habit of now stocking black boxes instead of grey ones. Or they'll carry grey and white boxes, but then have outdoor in use cover extensions that are black. WTH? And only in black!!! I've complained about it, that they only had them in black. No white or grey. No grey on order. It's regional whomever that dictates what they carry. WTH? Who has a black house? Who wants a black plastic box on top of a grey or white one, on the side of their house?! I sure don't! Just doesn't make sense.
Anyhow. Ordinarily I'd go for concealed wire and through the center of the box, but this is an instance where I can't do it.