People throw around the term like it's lost all meaning - usually when someone says they "bricked" their device, they're meaning that "it was moderately inconvenient to recover and I lost my data". Not that it's a literal brick that they now put in the garbage bin.
If you've got recovery, you've got an easy path to getting it up and running again. Just reflash your ROM, a different ROM, a stock ROM, whatever.
If you hose your recovery, you boot your phone into fastboot/odin/heimdall/etc mode which is built into the phone's firmware. From there, you can still flash images to the internal partitions to replace your recovery/system/anything else.
I don't wanna be the guy that doesn't include the "there's always risk" warning on his instructions, but if you're just flashing back and forth between ROMs the worst I'd ever expect you to mess up is wiping your internal storage and photos by accident.