Well it would beat the purpose of the application, wouldn't it?
The transactional emails feature has been developed because we needed to use it internally, i.e: to queue messages and not have the subscribers wait for the pages to load because smtp delivery takes time.
If we were to develop this feature more, you'd also need to add metrics, statistics, limits, quiotes and so much more things, which is the reason i say it beats the purpose of mailwizz.