You can do much more with AMP, not only marketing related stuff. Indeed, countdown timers can be done much easier with many tools (Nifty Images, Sendtric etc) without AMP.
AMP as described in this article provides a wrapper for some templated kinds of JS functionality. My comment wasn't specific to AMP, it was to the article's main point about "interactive emails" being unnecessary.
rchaud|10 months ago