I think they've forgotten that the purpose of Bonus Days (and seasonal events) is to induce people to play this game, instead of whatever other games they're playing (as I'm sure there is a fairly linear relationship between amount of time logged in and amount of dollars spent).
But weak bonuses and events with 0 new loot don't accomplish that.
For instance, if Snowpeaks festival had included new +1 and/or +3 festive augments, a lot of people would have spent every waking moment farming them. SSG has the ability to drive a lot of player engagement with very little effort/dev time/cost, they just don't leverage it.