You may not see why people would want separate accounts, but many people do. Sometimes the accounts are for different legal entities, such as work, personal, and for helping a charity. It is not correct to arbitrarily merge those.

Also, there may be different pay structures and packages used to pay for the services for each of those accounts. Hopefully, you can see how merging these can create far more work for the user, even when there are many cases that have negative benefit.