Ian Bicking: the old part of his blog

Comment

The point with Twisted threads is that you can start the threading (and enter your section of blocking code) at any level you want. If you really want, you can start processing in a thread almost immediately, turning Twisted (against its will ;) into a threaded application server. You don't have to adopt the Twisted style throughout.

But you also had another point -- if you eschew the Twisted style it becomes questionable that Twisted is worth the effort.
Comment on Twisted and Threads
by Ian Bicking