In short determining right tool for a task would be up to us, after required research and understanding on its features. But irrespective of its current popular usage and features the centralized architectures are bound to single point of failures such as, data theft/misuse, privacy, service down time, etc.
Important than that is, in a centralized architecture, when all data gets collected to a single point, obviously it will attract people with power such as government, crackers, owners etc. to exploit the pile of data and gain maximum out of it though it violates ethical and moral values.
Peer to Peer vs Centralized
Current technologies which we use in our day to day activities, almost for everything like storage, communication, processing, use Centralized architecture. P2P is not a single size fit for all solution against centralized architectures.
In terms of storage P2P is a kind of poor performer if you measure with utilization of optimal utilization of storage medium. But in-terms of communication, peer to peer solves single point of failure, prevents data theft/misuse, low latency etc.
Decentralized vs Centralized
Decentralization architectures would be suitable for storage related scenarios, where instead of storing a file in all the devices, you should be able to store your data in trustworthy places where you get access to verify its integrity.
For example, storing your valuables on local bank which you trust and verify its integrity when ever you pleased is always better, than storing in an unknown place blindly believing it is secure only because its owners says so and hoping nothing will happen to it.
Utilizing both Decentralized as well as P2P architectures in right scenarios as a replacement of centralized architectures will make much more sense in-terms of proper utilization or resources, and proper justification for ethical and moral values.