If they sent you the card, then you have the account. “Activating” merely confirms your receipt of the physical card. Yes, you should activate it. If you don’t, the bank may go through some work to try and contact you and trace the card. If you don’t activate it, they may close the account. Having a card closed after only a few months might look bad on your report. Having the account increases your available revolving credit and lowers your percent used, which is a good thing. If you need it and it’s not activated, it won’t do you any good in an emergency because they might have blocked the card (without closing the account) after a certain amount of time because they thought it was lost in the mail. Don’t waste a lot of time over-analyzing this. Just activate the card.

The account is already active and showing on your credit report. Whether you call the phone number and activate it or not.

If you don’t want to use the credit, don’t activate the card, if you want to build your credit activate it and use it on occasion and pay off the balance when you get your statement. You never know when you may need that credit in an emergency!

Hope this answers your question.

Might as well activate it, you already have it on your credit report that you applied and have the card. Activate it and use VERY wisely…
Don’t cut it up, you should use it occasionally to show credit activity. Like fill up your tank once a month with it then pay it off immediatly. (you do not have to do that, but it does show activity, activity as long as it’s paid in full and in a timely manner, can be a good way to improve your credit score)

Here’s a site might help answer your questions: