If you own a Samsung phone, there is a good chance that it has two SIM card slots. This is because Samsung phones are often used in countries that have dual-SIM cards.
Dual-SIM cards allow people to have two different phone numbers, one for work and one for personal use.
Some people might choose to have two SIM cards because they want to have a backup plan in case their primary number gets lost or stolen. Others might use two SIM cards because they have different requirements for their phone service.
For example, one SIM card might be better for international calls and the other card might be better for local calls.
Although some people might choose to have two SIM card slots on their Samsung phone, others might not. Some people might just use one SIM card and leave the second slot empty.
Others might use the second slot to store a different type of file or media than the first slot.
In conclusion, it is up to the individual user why they have two SIM card slots on their Samsung phone. Some people use them for backup purposes, while others keep them empty for different reasons.