'it useless' is not correct or usable in written English.
In written English, the correct usage is 'it is useless'. For example: "I kept trying to fix the computer, but it was useless."
Developing a good prognostics algorithm without the ability to quantify its performance makes it useless.
Freeze tells Batman that he has already developed the cure, but its instability renders it useless.
Its slow action renders it useless in arresting acute allergic attacks.
The problem is its high salt content, which renders it useless for agriculture or human consumption.
Many find it useless or distracting.
Knight couldn't see it, rendering it useless.
Con: Rough treatment can crack the filter, rendering it useless.
It went smoothly, but the cataracts render it useless.
The resulting unreliablity of the system renders it useless, Parnas said.
Unfortunately, his craft caught in tree branches en route to Manassas, rendering it useless.
She put unleaded fuel into her white-gas cooking stove, rendering it useless.
