Comparing phones is not only about screen size and camera count. Used devices should also be checked for exact model variant, region, supported network bands and software status.
Two phones with the same retail name can have different model codes. Those differences may affect firmware updates, carrier compatibility and repair parts.
A comparison page should therefore combine specification data with IMEI-based identity checks. That gives the user a practical view of both what the phone is and whether the checked device matches expectations.