If you don't use Emacs, it's probably not worth it. In principle, you could script it and use just as a timer (it's Emacs, after all, you can do (almost) anything with it), but it would be a bit of work for almost no practical gain.
When it makes sense, is when you actually use Emacs Org-mode. It's a swiss-army knife, built around three core "philosophical" principles: (1) you do (almost) everything on your computer within Emacs, (2) you keep as much as your stuff as possible in plain text files, and (3) if a user does not need a feature, it should not get in the way. So some people use Org as an outliner, some people use it for authoring books and/or papers, some people use it as a time management tool (and here my humble client kicks in), some people use it as a spreadsheet, some people use it as a literate programming tool, etc.
Now, if I have a lot of projects which I time-track in Org-mode, I get Beeminder integration for free. If I used some other tool, it would be much more time-consuming.
Coming back: now that I think of it, it would be (in principle) possible to built in something a'la Leechblock into my client. Of course, you could still circumvent it - after all, it's all open source - but it would be kind of a barrier to weaseling.
What I would really suggest instead, although I might be very mistaken, is as follows: from what you write I gather that your problem might really be located somewhere between the keyboard and the chair. What I mean, solving a psychological problem with technological means is very rarely effective (if possible at all). You might argue that Beeminder itself is a counterexample, but it's not: what is crucial here is not the technology itself, but the contract between you on the one side, and Daniel, Bethany and others at Beeminder on the other one. That's why it's so important that they spam us with personal emails, write a blog, and post a youtube video of a human being explaining Beeminder on the website: you get to know them (in a sense) "personally", and it's kind of hard to cheat a person when you can look them in the eyes (even on YT). I'm quite sure that Beeminder wouldn't be as effective if it were a huge corporate undertaking with no "human face" behind. Many people have little to no problems cheating a big corporation, but would not cheat a friend, a neighbor or even a stranger met in person. The technology exists here to remove some hurdles (yay for auto-updated goals!), but it is not the most important ingredient. As I see it, the two most important ingredients are: (1) the idea of the akrasia horizon, and (2) the fact that you have actual human beings on the other side. (The third one is that you pay with actual money, but it is not as important as the previous two.)
So what I would humbly propose would be to look for a psychological solution, not a technical one. Some suggestions that do cross my mind (in no particular order) are: (1) sending a personal email to one of the founders, promising that you won't weasel (and making it clear that you don't expect an answer, unless you want to land in a spam folder!), (2) doing the same on the forum or IRC channel etc., (3) writing such a promise for yourself and keeping it on your fridge or somewhere visible, (4) promising an actual, living, RL friend that you won't weasel, etc. You get the pattern here.