Art supplies are like going to the candy store... so many goodies, so much to play with...
I have since upgraded from the grocery store watercolor tray, but when I decided to get into watercolors it was all I had. And they work well!
Paper, for me, is an issue though. There is no question that watercolor paper is divine and is certainly made to take the moisture. But it's like using the good china for a weekday dinner. I am always worried I will goof and waste nice paper. I think the 'good stuff' should be for special occasions. So I use paper meant for drawing and doodling and then wish I had used the proper surface.
I must keep telling myself IT'S JUST PAPER!