It's not my personal preference, it's how its done. A bot is meant to look and behave like a human, how can you do so when you're over complicating something as simple as splashing by using your spellbook instead of simply left clicking the NPC?
Also, I AM entitled to leave my own review of the script and that includes a part where I either recommend or don't recommend this to other interested parties. So stop abusing your powers.
It clicks the spell that you've chosen in your spellbook and clicks it in your spellbook and uses it on the NPC. I suggest you ask him to change that to simply left clicking before purchasing, apparently he only listens to people who haven't bought it yet.