Yes, it could cause an automatic reboot if you are miser running it. If you run it only when you feel the system is slow you are ok then.
The answer is pretty clear here, NO, just try it and you will see. I challenge you to make a video showing the battery percent before and after running the script, and then same video but rebooting and that way we all can see if you theory about the MHZ at full load taking eating the battery is true. I already know it is not, like most of the people that use this script.
but extending it with additional "killall processes" stuff
There will always be n00bs reading. How can you prevent it? can you control the internet? Just saying.. Still, GOD bless YOU