As a developer I love to experiment new things and I did so with Gutenberg and the whole block system. But when it comes to clients' projects sometimes the time frame is tight and a "real" how-to guide would have been very handy: in my opinion that was missing for custom blocks apart from a few (not so useful for me) "hello world" examples. Therefore, since Gutenberg appeared on the scene a lot of my time was used in finding solutions with a trial-and-error approach or trying to understand the whole thing by reading (a ton of) code. I don't think it was a waste of time, on the contrary, I would have found it useful if only I had the time to enjoy it! That said, I really hope that for FSE there will be also a good guide for developers to get the most out of it while enjoying the learning process.