Why? Because the tooling is what ends up being used every day in so many ways. A minor improvement in tooling can lead to drastically better quality of life. It's like getting a fancy but expensive office chair - no, I don't need it, but my back will thank me at the end of every day.
The catch here is that this applies across the board. For example, many new languages try to sell you on a better language design that is more convenient - and it may well be, but it doesn't matter when there's no good IDE, no good debugger, no smooth deployment story etc. PL and API design is important, but it's not more important than everything else. The languages that are the best for "quality of coding" are the ones that balance it all, and usually they have to dial some advanced aspects down to enable other areas to work. Or at least move slower with language evolution, so that new fancy features get full support across the board. It's no coincidence that languages like Java and C# - which lag behind on bleeding edge language features - have the best code completion and refactoring in the industry.