Sure, well I would hope it's easy to do a one line deploy to any platform and with any language... once you set it up. You left out freezing requirements for pip, setting up cedar, etc. Nothing like that for a simple PHP app.
I don't want to overstate the case; deploying Flask isn't hard, but deploying PHP is stupidly easy.
I guess that's true, but you know... so what? Can't we worry more about building something cool than about shaving seconds off the one-time setup cost involved with sharing that cool thing with the world?
As a Mercurial user who doesn't feel like learning git just for the sake of deploying toy Python apps, can anyone comment on whether hg-git or the like is a reasonable way of deploying to heroku?
Of course, this assumes you are using Git in the first place, or are willing to learn it. Most folks already have FTP/ssh down pat, so git is a big jump from just copying files.