Summer weekends fill up fast, and the best backyard tents and string lighting setups get reserved long before the weather warms up. If you wait until June to book, you will end up paying a rush fee or settling for whatever is left in the warehouse.
A typical setup runs about $1100, which is a lot to drop in one single month. Spreading that cost out over time keeps your checking account from taking a massive hit all at once.
That 0% intro window is a deadline, not free money. If you still have a balance left when the 15 months are up, the company will tack on interest for what you owe, so make sure the tent is fully paid for before the clock runs out.