Does this question imply sharding would be more difficult with this sort of table design, compared with other table designs? Obviously sharding is difficult, b

Does this question imply sharding would be more difficult with this sort of table design, compared with other table designs? Obviously sharding is difficult, but what would make it any more difficult with this table design? Picking the sharding keys, avoiding hotspots, rebalancing, failover, joining disparate tables on different shards, etc... these are all complicated issues with far reaching implications, but I just don't understand how this table design would complicate sharding any more than another. I'm not trying to sound condescending and suggest it's a dumb question... genuinely interested.