Would you upload pdfs and things like that to your mediawiki? Bills, invoices, paychecks, for example.
I also have passports scans and other sensitive stuff. I don't trust that I can secure mediawiki well enough to put those in clear on the internet (in upspin they are encrypted with a local key and the storage is my own server, mediawiki is in the public cloud).
One of the big features I like in Evernote is the ability to search pdfs and images. I have a lot of technical manuals that I save, along with receipts/etc that are easier to search for.