Well, he put up an 87 wRC+ with almost a sub .100 ISO in 400 AAA PAs last year. I would rather he spends at least a month there and prove he's MLB calibre than him undeservedly making the MLB team and (possibly) blowing chunks.
And it's a depth thing too. If Pillar got injured Alford could have just came up and took his spot. Now if Alford and a few other guys get injured it's going to get real ugly, real fast.