You can tell visitors apart, and recognize them again
Personalization works on anonymous visitors and gets substantially better when it can tie a session to a known customer — and better again when it can join today's anonymous session to last month's known one. That is identity resolution, and it is an architecture problem rather than a setting. Where identity should be resolved across web, app, commerce and CRM together, the answer is usually Data 360 rather than anything inside the personalization tool.