If you're looking your day at nothing else but text it's the most obvious thing to spend time and money on to improve. Sure, it's an utilitarian thing at the end of the day, but why should it not look pleasant to your eyes?
I don't think I ever had _a problem_ with a font, but that does not mean I do not want to spend a bit of time and effort to improve my experience. I could probably also get away with a much worse keyboard or monitor and be just as productive. But would I enjoy it just as much? Probably not.
I'm not sure what you're referring to. The font is a one time purchase and significantly cheaper than a new monitor. Both things (a better monitor and a better font) can make you enjoy the things you're doing more.
Yes, there might be billions of free fonts out there, but the cost of that font is also not exactly making a huge impact for me that I have to save money there. Why would I start saving with the font all the sudden when I spend more money on literally everything else? Does not really compute to me.
I don't think I ever had _a problem_ with a font, but that does not mean I do not want to spend a bit of time and effort to improve my experience. I could probably also get away with a much worse keyboard or monitor and be just as productive. But would I enjoy it just as much? Probably not.