The thing is it is a short-term benefit, no real benefit that would matter in the next bull run may as well let new users get cards and have more money circulate in the economy.
I doubt Riftwatchers will sell out in a bear market so we will have another edition out and just have fewer cards. And fewer users if the packs are burned off.
Moving forward we are doing this anyways so letting this be a legacy of the old system seems fine.