This story is following directly on Ananias and Sapphira. I think the point is largely to affirm Peter’s authority confirmed by signs and miracles after the challenge implicit in the incident of Ananias and Sapphira.
So for me the doubts of authenticity do not come from these being miracles per se. The doubts come form the likely power struggle that occasions the report. Paul is much closer in time to the these events than Luke. Paul describes Peter as a moderate between the extremes of Paul himself and James and presents Peter as backing off from his convictions in the face of pressure from James’ people.
It is possible that Peter — the rock on whom the church is built was not a leadership candidate in the early days. Maybe he was a bridge builder seeking to reconcile hostile factions and dismissed as a fence sitter. This side of his character is shown forth in Paul’s criticism of him in Galatians and the claims in the gospels he denied Christ.
If this is true, and I have no way of knowing if it is, then the miracles and the commissioning by the resurrected Christ — all point to the judgment of a later period looking back and saying — yes, he was right. He was the peacemaker when we were at each other’s throats. And reading that new authority back into an earlier period.
Aak! I’m sounding like the Jesus Seminar folks now. Maybe I should start a Peter Seminar.