I can attest it's incredibly important. I am a new hire in Europe, I had been with this company for 1.5 months during which I didn't take 1 day of sick leave. At the end of the 1.5 months I felt really burnt out. So I called in sick on Sunday and told my supervisor I wasn't gonna be coming in this week. I am not actually sick, I am just really burnt the fuck out. I get 90% of my daily salary for the first 5 days of sick leave.
I feel alive again, temporarily. Fuck having to go to bed by x o'clock and wake up by y o'clock just to please some rich dumbass. Give me a 6 figure salary or stfu and lower your expectations, I'm not gonna give a shit about your bitch ass company otherwise.