While the reasons for these might be many, including security aspects (as one who uses your SIM can easily get access to your contacts), it does mean that the process of transferring contacts between devices can become cumbersome.
Mgbe ihe mere ndị a nwere ike ịbụ na ọtụtụ ndị, gụnyere nche akụkụ (dị ka onye na-eji gị SIM nwere ike mfe ịnweta kọntaktị gị), ọ pụtara na usoro nke na-ebufe kọntaktị pụrụ ịghọ cumbersome.