I've been doing work in Salesforce for the last 7 years in two different positions. Both are smaller companies in the Midwest (smallish city of ~100k if you include neighboring towns). I know of at least one other company in the area that is built on Salesforce. It's not the most exciting work in the world, but it's work that I know is providing value for the companies and people I work for/with.
Pros: Salesforce abstracts a lot of the DevOps/database work that I don't have a lot of experience with and lets me focus on building the applications we need. Much of my current work is building out Lightning Web components, which is your basic JavaScript web development work built on top of some pre-existing components provided by Salesforce. There is a ton of documentation and it's easy to pick up on things you need to learn.
Cons: Salesforce has a lot of quirks to it that you'll become familiar with as you get into it. Build/test/deploy cycles are slower than normal, but they are working on tools to make that experience better. In some ways, their focus on no-code is nice and it's really easy to get simple things done. In some cases though, it feels easier just to write code to get things done, especially if you suspect the feature you're working on will get more complicated over time.
All in all I'm not sorry for getting into this space. I've had enough variety in my jobs that I've done some work outside of Salesforce and I don't feel pigeon-holed. The Salesforce ecosystem seems to be growing and their is a lot of work available. I'm in my mid-40s so if I can get steady work over the next 10-15 years with decent pay, I'll be more than happy continuing work in this space.
FYI: I haven't bothered with any paid certifications though I do complete Trailheads when I need to learn something new as a way to both learn things and provide a signal to potential future employers that I know what I'm doing.