Yes. There are two principal reasons. First, the language is supremely simple and easy to use. Its entire syntax can fit on a post card!
Consequently, Smalltalk presents virtually no cognitive friction while using it. Many Smalltalk developers describe its programming as Zen-like.
Second, the language has a built-in, graphical IDE that supports live coding and debugging. This is enormously powerful. Moreover, the IDE is supremely simple and easy to use, just like the language itself.
Smalltalk is also image-based. An image is a memory snapshot of all the objects in the application and Smalltalk system. It can be saved to disk and opened again later.
This means that you can save the entire execution state of your running program and resume execution later from exactly where you left off! This is awfully convenient. The Smalltalk image can be likened to the system image in OS virtualization software like VMware and VirtualBox.