> It's also really tiny, and has a great async event-loop framework. It has built-in support for sockets and non-blocking I/O. It has a GUI toolkit that's pretty useful for making quick-and-dirty tools.

There are implicit "OR" statements between those sentences.

Example: suppose a newbie wants to use tk do make a quick-and-dirty GUI and leverage tcl's async event loop to make it responsive while processing a bunch of files. It's my experience that while this can be done it is less than easy.