Version 5 was kinda-sorta usable - but buggy and painful. In practice everyone would tell you to just download the nightly build of version 6 instead, as the UX improvements were massive. It became a genuine joy to use, and with the death of EAGLE the no-brainer choice for every hobbyist.
Since then development has raced ahead, with regularly scheduled released chock-full of both small quality-of-life improvements and new features focused on professional use. It's still a tier behind the likes of Altium, but these days KiCad is a very solid choice for everything but the most high-end PCBs.
It is definitely good enough to build your small consumer business electronics business around, which means there are suddenly a lot of potential users willing to throw a few bucks at it to solve the remaining small papercuts and missing features they run into.
By the time I picked Blender up in 2016 (before 2.8!) it felt pretty mature, but I used it (still) because it was the one that was free and which worked on Linux.
The time and energy I put into learning Blender feels like an investment that has paid off amazing dividends.
(I'd also picked up Godot at the same time, with much the same story of elation on its adoption rate).