What's the reason for getting a second credit card?
If it's a different credit card brand, then that's reasonable since some places only accept one kind while other places accept other kinds.
For instance, I know that some places do not accept American Express.
If it's a different card to be used in emergencies, then that's also a good idea.
I have a friend who has several credit cards. He has a VISA, Discover, American Express, and Mastercard. The VISA is for Best Buy. So, when he shops at Best Buy... he gets lots of bonus points to use for future purchases. His American Express has frequent flyer benefits. Since he flies a lot for work, it benefits him. His Mastercard has hotel benefits. His Discover has big personal benefits, but he can't use it everywhere. That's why he has the other cards.