I had a very similar chip in one of my grandmother's tanks. It was a 5 gallon. I had noticed it was leaking, but had not noticed the chip right away. There was a leak in the silicone on the bottom of the tank. As I was replacing the silicone on that part, I noticed the chip. I poked at it a little to see if it was leaking, and it wasn't. However, the glass chip could've easily been removed. Since I was already siliconing anyway, I just repaired the chip. It makes me much more comfortable knowing that the chip is reinforced, If you have silicone, repair it. I found a small tube at my LFS for 9 dollars. I was a little disappointed in the price, but happy with the results. And it's always good to have aquarium silicone laying around, anyway.
So, I guess it's a matter of whether you're confident in the stability of your tank currently. If it;s not leaking and you aren't worried about it, I wouldn't bother. Just my opinion.
