That makes it look even more unimpressive. Like, can some art folk explain what's so great about it?
First of all, you mustn't think about it in terms like "why does it worth 300 million dollar".
The price tag is a function of the fact that there is a finite and rather small number of Gauguin paintings out there (and even fewer of them are for sale) so all it takes a few very rich people to push the price to such levels.
In any case, it can be quite difficult (and some would say impossible) to explain why a painting is great, but I can explain to you why Gauguin is important.
You see Gauguin was in large part a bridge between impressionism, probably the most important art movements of the 19th century and THE defining movement of the 20th century - modernism.
So not only is was he directly influential on many great artists that came after him, his work sort of stand suspended in the ever romantic gap between the modern world we live in the old world it replaced.
Now I should note that the reality of art history is actually much more complicated than such simple narratives - he wasn't the only artists occupying this space, and not to mention that expressionism in and by itself is in large part a reaction to the quickly industrialising world, but that perception surely help cementing him as one of the most important artists in history.
Also, his colors are really really pretty.
I like colors.
I know dick-all about art, but I seriously love looking at a lot of Pollack's work.
He just hacks your brain, standing in front a Pollock is one hell of an experience.
And for the people who think this is easy to make a Pollock or even Rothko, why don't you try?
I don't think that degree of difficulty is a good way to measure art's worth, but as pretty much any person who ever tried will tell you, that shit is harder than it looks.