IPFS doesn't require any blockchain.

In fact someone could easily setup some IPFS nodes that fetch the data from the current host if requested over IPFS.[1] This way people could access it via IPFS and provide an alternate mirror of the data.

[1] https://github.com/ipfs/go-ipfs/blob/master/docs/experimenta...

The main benefits here would be

- Even if the source is unavailable there may be other copies on IPFS which would be transparently used.

- There may be some performance benefits in rare cases.

- If you are accessing this on a bunch of machines your IPFS gateways would handle downloading the source once, then automatically using the local copy from inside your network.

The maindownside is that if Amazon is donating their resources why bother with IPFS?

That's not correct. When it comes to storage and transfer, blockchain alternatives are fraction of the cost of Amazon. For example Sia Skynet is offering $5/month/TB[1] storage. If you skip Skynet and run your own Sia node the price can even go lower to $2/month/TB basing on the market conditions.

[1] https://blog.sia.tech/announcing-skynet-premium-plans-faster...

Moreso than Amazon? From my (limited) experience blockchain storage solutions are often less expensive, although I've never worked with petabytes of data so maybe it's different on that scale.