Agreed. I hastily installed FF Preview and then immediately uninstalled it when I couldn't find where to install uBlock. They shouldn't have launched, or made an announcement, without some form of adblocking (native or plugin).

I understand that it's a testing release, but they stand to lose out on many testers and users. While I am perfectly willing to be a guinea pig and use this as my daily driver, I am passionately unwilling to browse with ads (especially on a mobile device where data is more expensive).

I am likely part of the vast majority of potential testers/users. There probably won't be a "hey, we support plugins/blocking now" announcement and, even if there will be, it probably won't be as visible as this announcement.