Writers have relied on their words only to convey emotions for a very long time. It's only recently that we've been drawing faces next to our words instead picking good ones.
We've been drawing faces and other emoticon-like symbols next to our words long before the internet. (Think informal writing like postcards or notes.) People have illustrated their writing for even longer. (Think medieval manuscripts, as an extreme example.)
Even canonically great writers don't (as a whole) limit themselves to words- they write plays that include stage directions, they write poetry that plays with layout and punctuation, they write songs that include melody and instrumental parts.
It's really only some forms of formal writing that limits itself to words to convey emotions.
[guiñando] [CARA_TRISTE]
Now, what the fuck did I say? Can you figure it out? What if I chose different words?
If i was to explain my emotional state and intent on every other message i send, chatting would become rather laborious and having a fluent conversation much much harder.
Indicating that beside my contrary opinion my critique of your comment isn't a try to bluntly dismiss and educate but rather an act of wanting to partake in the conversation in a benevolent way takes me a good third of what I am writing. Or i could just :)
Text can convey fantastically deep and moving emotions. It just takes a more investment on part of both the author and reader than images.