User blog comment:Comrade Hamburger/Black Ops III Season Pass Owners Receives Bonus/@comment-1916935-20160506182349/@comment-1187559-20160506192913

I wouldn't be surprised. I reckon having the weapons essentially behind a paywall puts people off getting them and playing MP (since unlock tokens take forever to earn for a decent SD). Also making it for SP holders likely makes getting it a bit better, since this way you actually get something more than just maps. Something Battlefield has been doing with Premium for much longer.