"it's pointless to" is correct and usable in written English.
You can use it to express that it's not worth it to do something. For example, "It's pointless to argue - let's just agree to disagree."
It's pointless to repeat modernism's experiments — what's the point, in science or art, of reinventing the wheel?
The truth is nobody knows what Kevin Durant will want in a year's time and it's pointless to speculate.
If it has, the commander's intent is no longer valid; it's pointless to continue with the original order.
Skinner argued that it's pointless to imagine what's going on in an animal's head.
Walker's later work just operates on an entirely different level and it's pointless to pretend otherwise.
Perhaps, in the end, it's pointless to make comparisons, because however you look at it, Curry's season has no precedent.
It's pointless to discuss it.
"It's pointless to unpack these things.
It's pointless to claim otherwise".
It's pointless to alienate him, and not good business.
It's pointless to pretend that that's not an issue.
