Bad for what? Gutting it, I wouldn’t. Recycling centers, local salvage yards, and even many places online will buy these used cats for a bit of cash so long as the precious metals are still in them, so you can likely get a bit toward the purchase of a new cat from it so long as you don’t gut it. Don’t expect alot, but $30-$100 depending upon market and who you sell to, still ain’t bad. Ebay would likely pay the most, but the most pain…
http://www.ebay.com/itm/IMPORT-OEM-FULL-Catalytic-Converter-SCRAP-Recycling-Platinum-Palladium-Rhodium-/331172509434
Were it me, I’d leave it out or make some kind of makeshift patch if you can’t replace it right away. If you run with it, you run the risk of bits of it getting thrown into the muffler. Instead of $300 fix, you end up with a $600 fix.
Realistically, it’s not that big a deal IMO to run without it for a bit. I’ve used 2 store bought patch sections before (clamped together) to create a temporary patch before just to get me by for a bit, and without getting ticketed for noise pollution in the meantime.
I’ve just left ’em open air before as well, so long as it’s not that long a time, and you don’t sit next to a cop at a light, or get up really early for work making the neighbors irate, it’s not a biggie. Just remember in addition to pollution both noise, and air, expect it to run rich in addition for that time.