Please just call me either J. or by my name, Jeroen... I always feel old when people call me "sir"... (At least you didn't fall for the girl in my avatar as I am indeed a man). (I accept J. from English speaking people as I know I got a hard name for you guys to pronounce. I'm Dutch, that's why I got such a "strange" name).
And what is "safe" or "unsafe" is always hard to predict... JavaScript in particular has changed a lot over the years, but then again so have C and C++, so when I have to look things up (hey, I can't remember everything, especially not since I code in multiple languages) I really must mind the date on which stuff is written. Overall I do feel safer with my own solutions too. But there is always a risk of "code rot" (which happens when programming languages change so much that code no longer works). However when you work low-level you are less bound to the changes as when you work high level. I've also had to ditch a few old frameworks in the past because the author discontinued them or neglected them otherwise. When you only deal with your own code that's less likely to happen. The downside is when the underlying language changes that you must update everything yourself also, and with ready-to-go frameworks their respective authors must do that, but downside is you gotta wait for them to get things up-to-date.
I think if you are used to work with your own stuff and if you are satisfied with that, why change? It's not that games made in Unity are per definition better than games written in C/C++ or vice versa.
And yes I too like to write my own tools whenever I'm able to. Of course, I am not gonna code my own defragmentation tool... as I really feel I can better leave that to the professional software industries, but I have written loads of tools I use every day myself, and some of them may not be easy to understand for others, but hey, for me they do what I want them to do. And if you look around in my github repositories (I got by the name of Tricky1975 on github) you will see that I have stuff written in C, C++, C#, Python, Lua, BlitzMax, Pascal, Go, well, anything... It's just what I thought I needed to do the job best at the time...
And thanks for your appreciation.... I always like to use my own experience to help others. There was a time I was a beginner myself, and back then we had no internet, so I was much more on my own back then... Oh, crap, now I sound like an old man... Hey, I'm just a boy... a boy in his forties, but still a boy ;)