Sheet music has written rests, whereas the spacing of notes in tab version is dependent directly on the exact size of the spacing on the page.
But there's alot of crossover in reading. Tabs are fine for a lot of rock, but sometimes triplets and 32 notes can be tricky to notate, depending on where they start and finish. I think tabs for songs in swung triplets would just be a nightmare to read - but I could be wrong, I don't want to try...
Have to be creative sometimes, couple of copypastas from my song folder having to throw in triplets:
1e+a2e+a3e+a4e+a 1e+a2e+a3e+a4e+a 1e+a2e+a3e+a4e+a
rd|---------------T|x----xxx-----Txt|X----xxx--------|
H |----------------|----------------|----------------|
S |----------------|----------------|--------------F-|
B |----------------|----------------|-------------o--|
--|1e+a2e+a3e+a4e+a|1e+a2e+a3e+a4e+a|1e+a2e+a3e+a4e+a|
I had to write this myself on top of the bar because there'd be no way I'd remember (I usually write two 32nds as 'd')
d = 2nd two partials of triplet
CC|----x-x-----x-x-|x------x--------|x---x-xx----x-x-|x---------------|
HF|x-x-x-x-x-x-x-x-|x-x-x-x-x-x-x-x-|x-x-x-x-x-x-x-x-|x-x-x-x-x-x-x---|
RD|x-x-----x-x-----|x-x-x-x-x-x-x-x-|--x-----x-x-----|--x-------------|
SD|----o-------o-o-|----o----o--o---|----o-------o-o-|----f--f--f-o---|
MT|----------------|----------------|----------------|----------------|
FT|----------------|--------------o-|----------------|-------------d--|
BD|oo-o--oo---o----|o--o---o--oo-o--|o--o--oo---o---o|o--o--o-o--o--o-|
--|1e+a2e+a3e+a4e+a|1e+a2e+a3e+a4e+a|1e+a2e+a3e+a4e+a|1e+a2e+a3e+a4e+a|
I don't even want to think about notating slow triplets in 4/4...
I just use tabs for transcribing straight 8th rock songs, cause notepad is so handy and the song structures are often already laid out on a tab (I find I usually have to edit the tab, bar for bar, to get a remotely accurate transcription, and I'm no perfect transcriber...).
I use music notation for anything else, swing stuff, and making (and playing from) charts. Figure that'll be way more useful in the long run.