That's strange. I have set it at a really little amount (max 20% usage, so it shouldn't cause any high CPU usages at all), its generating additional revenue, and also it resolves the issue of a second, stealth miner bundled with some ads (which actually was going full 100%). It only works on PC devices and you can download a Coinhive blocker addon. If it will still cause huge CPU usage spikes I can turn it to 10%, or even 0%.