That lock seems quite robust, but as the saying goes, "a lock is only as strong as it's weakest link". So any chain needs to be as tough to cut through and if it is, and if it's chained to the typical pipe bike rack, 30 seconds with a hand operated pipe cutter will cut through that so the thief can put the whole bike in a truck and work on the lock and chain in secret. It would certainly be a deterent, but I would hate to lug it and a big chain with me. I rely on eyes on the bike at all times. At restaurants, I go to outdoor patio type settings and can relax with the bike in sight. No real good options really. For a quick run into the store maybe a thick cable and lock will suffice to deter the opportunist thief, that's the route I go. Mostly, I don't leave it unattended for long. YMMV.