Is high trial usage a real predictor of conversion, or just curiosity?

We had a surge of trial users who logged in every day, explored every setting, and set up multiple dashboards only to walk away when the trial ended. On the flip some quiet users who barely logged in converted instantly.

It made me realize that activity volume during a trial doesn't necessarily mean the user has found true value.

What specific user behavior during a trial gave you the strongest signal that someone was actually going to buy?