This is a great question that is so often echoed in the frustration of people and businesses while setting up a merchant account. Yes, there is a lot of information required of you. Be happy of that. Why? Let me give you a scenario...
I am a crook and I want money. How do I get it? Well, I have a computer, an internet connection, a camera, and a merchant account. I go trolling for old cars. I find a 1968 Dodge Charger with a Straight Six in triple black sitting in someone's driveway. I get a good picture of it. I then go home to my den of crime and upload my new photo on my computer and post it in eBay. I say that it's my recently deceased grandfather's; and though I love it, I cannot bear to have it around now that he is gone and I put a price of $5,000 on the car. As that is a fraction of the car's worth, it is snapped up immediately, they pay via credit card, I get my money in 48 hours and the buyer wonders where the car he just bought is. Why? I am gone. Long Gone. I am a crook after all.
Now it is not as easy as that for one important reason: it isn't that easy to get a merchant account. That is because one doesn't need a mask, a horse, a six-gun, and an empty sack with a dollar symbol on it to be a crook anymore. You just need a computer, an internet connection, and a way to process money (hint: insert the term merchant account here). Merchant accounts deal with money; and that's the one thing everyone wants. More importantly, it deals with the way money is passed from Person A to Person B. My father is an attorney and he has always said that, "99% of all laws are about money, and 99.99% of those laws are about Person A passing money to Person B. Because THAT is a taxable event."
Not to mention, there is substantial underwriting and risk involved in merchant accounts due to possible fraud. Although the world will tell you that credit cards aren't real money, they are magical gift making machines that taste like happy; in fact someone does have to foot the bill. If a credit card transaction goes bad, either the issuing bank (the company that created and sent out the credit card), MC, Visa, Discover, American Express, the business where the bad transaction happened, the Fed, or the card holder is going to foot the bill. Somebody, and I do mean somebody is absolutely going to have to pay it. Whether it's for $1.35 or $50,000, somebody must pay the bill and generally that someone is the business involved and their merchant account.
In fact, we normally think of the majority of all credit card law protecting the card holder. That though is patently un-true. They protect in this order: the Fed, MC/Visa, the card issuing bank, the card holder, the processor, and finally the business. Unfortunately part of this is simply because a business can be run so poorly as to violate the system and run costs up, while the card holders are voters and their senators want sound-bites saying that they should be protected, even if they buy $100k more than they make in two years.
Finally, let it be said that the processors which are getting all of this sensitive data on you are to be trusted. They have to go through extreme measures to make sure they are protected in ways that most people could never dream of. Secondly, they have their hands all over not just the money, but the most sensitive of all: card holder data. That is to say the name, card number, and expiration date on the credit cards themselves. If they were to ever get hacked (and there have been some extreme cases), they are very liable for all of it and can be sued by each and every card holder, as well as getting delisted by MC/Visa.
In short, all that data is to make sure you are a real person and you have a real business. They are weeding out people signing up their deceased relatives with fake addresses at the mall or post office. You are real. Your business is real. You have a real address.
Welcome to the world of business.