What is the big deal about hand written invite envelopes exactly?

Just out of sheer morbid curiosity here...because according to the people who feel the need to comment on it daily, I have absolutely atrocious handwriting. I regularly get told I have chicken scratch or that I write like a drunk five year old (yes, those exact words). And everyone else I know can write well but even theirs starts to go downhill after more than an hour of writing. So between crappy handwriting and wrist cramps, plus not wanting to burden anyone else with what should be entirely the responsibility of myself and my fiance, why do some people still seem insistent on hand written envelopes? Because I have never once been to a wedding and heard a guest say "Oh its a lovely wedding, but did you notice that they PRINTED address labels?"