Moderator: United Airlines
Join Date: Jun 2007
Location: SFO
Programs: UA Plat 1.995MM, Hyatt Discoverist, Marriott Plat/LT Gold, Hilton Silver, IHG Plat
Posts: 66,856
A major issue for SMS or e-mail 2FA is for travelers who may or may not have access in certain parts of the world while traveling (separate from the issue of how secure those are in parts of the world.)
The weakest link in the process is the user re-using account passwords on multiple sites. Even the "silly" questions can improve the situation for those folks.