You struggled, you sweated, you truly took the time to find the exact right words to tell your future spouse precisely what s/he means to you.  After all of those sleepless hours spent staring at the ceiling and thinking, all of those drafts and revisions, you finally did it - the hard part is over.  

...Now, when it comes time to stand before the love of your life and officially join your life with theirs, do you really want to read those words off of your phone?