It's not going to hurt the processor, might increase the battery drain.
I personally wouldn't be paying much attention to the "experts" on YouTube.. But if you think that it looks better.. go for it.
What device do you have?
Normally, there shouldn't be any noticeable benefits to turning animations off, unless you have a device that has an inadequate processor, or Kernel settings are not where they should be.
Since we can no longer Root most Samsung phones, these tweaks aren't possible any longer.. not to mention that most people didn't understand what they were doing.