It's definitely a prototype project and doesn't have the convenience of say dropbox. dropbox has multiple well working apps on multiple platforms, which makes it more convenient for the mass market.
I've seen Sia being used by small business owners and such due to cost savings if they have large amounts of data.
Are file transfers fast enough to be useful for a biz? Maybe a photographer or something like that?
I have it running and have some files uploaded. It is pretty cool and I love not relying on Google, Dropbox etc. The only way to get around these central points of failure to to *bypass them. That's the whole point of crypto, right?
ive just been testing transfer speeds using the 1.3 wallet and sadly it is very slow even using my 300meg connection, (i uploaded about 2 gig of lo res photos to test). I think this will get better as the wallet is developed and am currently a host myself making a menial amount of coins per week but im glad to be helping the network and look forward to the future! (my current Sia stash is 80,000SC - Hodl like crazy)
i've seen a few reddit posts where examples of usage. It depends on their purpose - achieving vs file transfer between clients.