Not totally clear on what this is or what it would be used for. Transfer to where? Would be nice to hear a usage scenario.

I can only guess this is like an FTP-ish portal concept where designers and clients can share large files that are too big for email.

Wetransfer is a simple file transfer app, you select files on your phone or pc, add an email address and that person gets a link to a zip file with the files. i assume that now you can add files you bought from istock straight from the site to the api and send them in similar fashion to any email address. dont see the issue, it just makes it easier for a buyer to share their purchased images with whoever they need to share them with

Buyers shouldn't need to "share" a file with anyone.  Especially since the license is non-transferable.

http://press.gettyimages.com/wetransfer-launches-new-api-with-istock-by-getty-images-as-their-inaugural-api-partner

Can someone buy my file and transfer it to who ever right from iStock? I thought dropbox had this covered. Is this a need for
the buying community?

The person with the access/money/budget is not necessarily the same person as the one using the file. Imagine the marketing guy picking the image but the graphic designer needs to integrate it into the brochure.

So I guess many downloaded files are being send over email these days already. I can see why and how it happens (and how it still is legal). So why not make it a step easier?

Well but all that aside, I guess it's primarily a mutual marketing agreement between Getty and WeTransfer. Customers from both services get to know the other. Quite common.

what if someone hired a designer and he purchases the images on istock and then sends them to the designer, nothing wrong with that, think outside the box