No. Not all tips are pooled on all cruise lines. When good service is rendered, it is appropriate and courteous for a gratuity (Tip) to be extended personally. In the case of the cabin steward, this is not always possible as they tend to only appear when you are not in the cabin! Many cruise lines now automatically access the tips to your sign & sail account, therefore, you don't have to worry about the correct person getting their gratuity. If you wish to change this, just go to the pursurors office (desk) and request a change; delete, add or decrease the amount.
You could do that. The room steward would love it. He would pocket the tip and thank you very much (in absentia). The waiter would then wonder why you stiffed him.
One of the reasons they instituted auto-tipping is the problems they had in the past with the wrong people getting the tips, the suspicions and finger-pointing, sometimes the fist fights between service staff who had not received the tip they had hoped to get - and suspected that one of their colleagues had somehow stolen it.
Please give the tip to the guy who earned it. You will both be happier.