What if your top choice offers you an interview in February but you already spent all of your cash attending other interviews? Yes, it is a big what if. But it is a problem resolved by having a well tailored school list that factors in these possibilities. Obviously in my example you take on a little bit of credit card debt, but still. It is something to consider when making a school list in my opinion.
I totally get it. I saw it happen one year where someone actually had to turn down a late II to Penn because of money. It happens.
@gonnif's point, which is correct, is that none of us has any way to know, going in, where we will get IIs and where we won't.
It sounds obvious, but it bears repeating. If we knew, we wouldn't waste time or money applying anywhere where we weren't going to receive an II, or an A for that matter. So sure, in hindsight, you'd apply to less schools in order to have money to take the February II, but, at the outset, you have no way to know that the dream school II will ever come, and that the schools you knock out wouldn't have ended up being your best option.
I know it's tough to hear, but, whether you need to use credit cards, parents, student loans, or a part time job, I'd look at this sort of like a business endeavor. No one who knew what they were doing would under capitalize a new business, which is a recipe for failure. Same here.
Even if you have to delay for a year (which I did last year for different reasons) I would not start this without knowing I had enough money to see it through, which means having enough money to submit every application that it makes sense to submit, and taking every II I was fortunate enough to receive.
JMHO, but, ideally, you want to do this once, and want to maximize your likelihood of success. Running out of money before being able to interview at your top choice to me would be like running out of money right before your business was about to hit it big. You'll spend the rest of your life wondering "What If?".