While reading manga a character stole a power from another guy and said:
I wonder what's the use of the て-form in みたい?. What would be the difference with こいつの力を試してみたいな
It's an example of te-form for reason, but the subsequent part ("I'm doing this" or "I stole this power") is omitted because it can be inferred from the context. In short, this te-form means "because".