Using flashdist is a quick way to create OpenBSD based test environments on flash systems. It works well in an environment for production systems that will experience frequent, partial changes (new kernels, new daemons, etc). It's also for people getting their feet wet with small systems in general.
flashboot:
If you are seeking to create a traditional embedded firmware image with OpenBSD, I would suggest looking into flashboot. Flashboot boots from a single image (a ramdisk kernel) that populates a RAM disk on boot. The entire system then operates from RAM. This is in contrast to flashdist, which sets up a system that reads the flash ffs filesystem on demand for executables and shared libraries (Much like a traditional OpenBSD installation.)
Naturally, there are a few pros and cons to each method. For instance, a flashboot system will be easier to upgrade remotely with entirely new images. It may also start up applications faster, as RAM is faster than flash. To contrast, a flashdist system will be easier to patch together, more like a typical OpenBSD install. You can upgrade or change single binaries without reinstalling the entire image. It will also leave more of your RAM open for application use. No matter what you use, flashdist contains a lot of practical methods for getting things done, and you can pick those up quickly just by reading it.
others:
There are lots of cool packages out there that are flashdist inspired and others like flashboot that are completely different. I'm glad that people think it's a useful idea. But, I'm not listing them here anymore because I don't keep track of them.