JASS?

So I've been wanting to give this a shot and I've read some tuts but I really just don't get it. What are the benefits of JASS. It just seems like anything you can already do with GUI it's just decoding the already user friendly program. Anyway I've been making a ton of spells lately and I've been inspired by a ton of the spells off this site and from games like DotA but they all use JASS. Why not just GUI? People say it's not possible (or practically impossible) but isn't GUI just taking confusing code (JASS) and making it understandable? What's the difference.

No.

There are some main differences

1) Jass is more efficient. The code will sometimes run faster.

2) The code is more modular. You want to change the 100 damage to AGIx3. No need to go through ten menues choosing every function, instead it's just to type it down. GetUnitAgi(u,true)*3 Faster to type!

3) Portability, it is easy to copy paste Jass, it's irretating hard to do it in GUI.

4) Something more

5) Something more

There is no advantage of GUI. There are advantages of jass.

Ah, the everlasting question... to be short, most people here use JASS and vJass instead of GUI because:
vJass > GUI * Infinity

These threads have some good amounts of information about the subject:
[list]
What can you do with Jass that can't be done in GUI?
Is GUI still good enough?
Differences of JASS and GUI

There are a lot more threads about "GUI vs JASS" around, but I didn't find them... however, these should suffice.