It is not worth it for most people but if you want to overclock and push your CPU to the edge I would recommend this over the regular one. Here is why:
My very good friend saved money for months and he bought himself a new system. 9900K Strix Z390-E board and Kraken X62 cooler with a plan that he doesn't need 9900KS, and he will just OC 9900K close to those speeds. But...
I think that he got the worst 9900K on the continent. No matter what we did it wouldn't go past 4.9GHz all core. And he really wanted to reach 5. He then went and bought a custom WC loop so we could ramp voltages a bit more without the CPU soldering itself to the motherboard, again, it wouldn't budge. He always wanted a custom loop, this was an excuse to go and do it. Then he ordered a de-lid kit from Rokit. After days of waiting we de-lided the chip and lapped it. But no matter what we did it wouldn't go past 4.9GHz all core.
The sadness and disappointment on his face when he settled on 4.9GHz... OMG Just buy KS. Those $150 more are nothing.
Don't get me wrong, he would have probably water-cooled and de-lided 9900KS but those $150 extra guarantees you that you won't get a dud. And trust me, after being with him through all the pain and suffering I would gladly pay extra for KS at any time if I was building a balls to the wall system.
It is that enthusiast thing that we all have in us, and we pay more for the privilege.