I should add that one issue with org-tempo is it doesn't seem to be backwards compatible with old templates. For example packages such as ob-sql-mode and org-reveal have easy templates based on the old format such as :
(add-to-list 'org-structure-template-alist
`(,org-babel-sql-mode-template-selector
"#+BEGIN_SRC sql-mode ?\n\n#+END_SRC"
"#+BEGIN_SRC sql-mode ?\n\n#+END_SRC"))
This causes the cryptic error "File mode specification error: (error Format specifier doesn’t match argument type)" when trying to load org-mode which took me ages to figure out and could potentially turn someone new to org-mode/emacs off forever.
I think this would be a good reason to not enable org-tempo at least for the time being until either it can handle templates in the old format, or produces a less cryptic error for users.
Regards,
Kevin