Does that change the usefulness of the card during this period?
It might. It's not quite like being able to pull $5000 at once and use it to pay off a high rate card (although that may be an option for a one time fee) or to take the money as we did in the old days and buy a 12% CD.
If you have a planned purchase, and were saving towards it, you can use the card to buy it now, and pay it off at no cost. The fact is, rates are so low, that if there's no high interest debt to pay, your savings isn't likely to be earning much interest anyway. Be sure you make the minimum payments required and are ready to pay in full when the 0% goes away.
One issue - as I recall, this is your first card. We generally advise to keep the statement balance to less than 20%, or even 10% of available credit, above that will impact your credit score. The good news is that if you max out the card, buy your furniture, and pay it to zero at the end, your credit score will right size itself. Just be aware, and don't panic. In my own experience, I saw just under a 50 point hit, from 800 to 750 for excess utilization (above 30%) and those points came back as the zero loan was paid down.
Is it more acceptable...?
That's a judgement call. One camp says "don't buy it if you can't pay cash, or balance in full each month." I'm from the position that "knowledge is power" and as long as you aware of the costs involved in your decisions, the result can be rational. e.g. "I'm willing to pay $xxx interest over a year's time so my apartment won't embarrass me when a guest comes over." Debt and interest aren't evil, interest is a choice just like dinner and movie vs cooking at home is. What I do warn about is to avoid the permanent card balance, so a purchase at age 23 isn't still being paid off in your 50's. I've seen that, it's not good, by any means.
