The roof is too small. Those logs are going to get wet.
There actually is a story behind why I was looking up outhouses on the net. It's based on one of those bizarre things you see every few years. I'll be glad to share it if you really, truly just can't live without knowing. :)
I gotta say, when I'm looking for an outhouse, the internet is the last place I would go to find one!
The logs appear to be milled but nonetheless, it is butt & pass...