The difference to YouTube is that it's not intended to create a huge platform centralizing videos from the whole world on a single server farm (which is horribly expensive).
’S e an diofar eadar PeerTube is YouTube nach eil e ag amas gun dèid ùrlar a chruthachadh a chuireadh na videothan o fheadh an t-saoghail ri chèile air an aon tuathanas fhrithealaichean (is bhiodh sin cianail fhèin daor).