There's (almost) nothing worse than stumbling across a project written by a bored developer and then having to support it. Instead of a perl script and some SQL, it will use some smattering of the techs that you mention above. Often not for any real reason, but just because their job isn't demanding enough so they make it as interesting as possible. But it's better for everyone if you do this on your side projects - when you leave your CRUD job someone else is going to have to maintain the wobbling stack of technologies that you used to pad out your resume.
Using things where they don't need to be used is always wrong, but that's almost always just the consequence of a bad developer writing stuff. Not a bored one.
Great portion of developers aren't "bored", they are bad, so they do everything as they go, without optimizing, without planning, etc. When they try using different things outside of their limited knowledge base, they screw up even harder. Creating the unnecessary complexity you talk about.
I find refactoring/optimization to be a necessity and even tho my boss probably won't ever know I optimized X, I know I did it, and I will keep doing it. It's how you grow as a developer, specially in CRUD companies that do not care.
And keep in mind, most developers don't want to get out of the CRUD. And they are very happy with a good paying CRUD job.
I completely agree with this. If you write otherwise simple systems with the latest and greatest technologies, you will often be force to maintain them yourself. The original question was about career growth -- I've seen good developers get stuck in positions that they should have outgrown because they chose technologies that only they could maintain.
Keep your pulse on new technologies, and write your own to expand your expertise. But don't use the wrong tool for the job out of boredom.
Well, I had the opposite experience: as the developer wasn't curious, I had to maintain a codebase with custom (incredibly inefficient) SQL queries instead of a search engine, custom code for which gems exist, pages were never optimised so they became slower and slower etc. in the end a complete rewrite was needed.
As @trustfundbaby says, you can apply new techs sensibly and that's what you should do, without the extremes.
And guess what? You could actually learn something from someone else!
