Tax is the wrong word... It's not the case that the Clojure (the language, the developers, etc) benefits from slow startup. Fine is probably more accurate.
"Performance" is never the end-goal, but rather a coin you can trade for other things, like convenience, lower latency, fewer hardware resources, getting results faster, scalability, etc... basically anything that makes you or your clients happier. When people say they want performance, they actually mean they'd like the flexibility to gain something else by paying with performance.
That's why I used "tax" which I think is very suitable.
Actually part of the reason startup is slow is that the JVM's JIT compiler doesn't optimize its compilations until it's determined that a given method is in a hotspot that would benefit from the optimization. Because it relies on runtime information, it's able to perform much better-informed optimizations than it would with a fully up-front compiler, but the price you pay is that the optimizations are deferred.
