A Turing complete script can read and write data on the block chain, so in theory it can do anything a block chain core protocol can do. Of course performance and other issues may be not be optimal. Yet one can reason that the script can be hard or soft forked into the core protocol to improve efficiency if there is popular demand for the feature.
In theory. You know an old joke comes in mind about "in theory". Let me share it:
A little boy asks his father, "What's the difference between 'theory' and 'practice'"?
The father thinks for a minute and then tells him to go ask his mother and his sister if they would have sex with any many for a million dollars and then report back to him their answers. The little boy asks him mom first. "Mom, would you have sex with any man for a million dollars?"
She thinks about it and then answers, "Yes, I would."
The little boy asks his sister, "Sis, would you have sex with any man for a million dollars?"
She doesn't hesitate, "Yes, I would."
The little boy runs up to his dad.
Dad asks, "What did they say?"
The little boy says, "They both said they would".
The father says,"There you go, son; in theory, we're millionaires, but in practice, we live with a couple of sluts."