Most healthy food cooked properly are bland and tasteless. Cooking with MSG give the same food some flavor and taste.
MSG gives an aftertaste, making your tongue appears white and dry. It doesn't melt or dissolve in high heat, so the common belief was that MSG would stay and collect in your body for a long period.
But critics fail to point out that MSG dissolve naturally with water, so drink enough and MSG will be pissed away.