I have had a 770-790 credit score for almost 20 years and using Bill Me Later, Capitol One or anything else doesn't make that much of a difference.
For most humans, who may have made mistakes in their pasts or who may not have well established credit, it becomes important to watch and manage hard hits on your credit report. Anyone who has lost a job to the economy or suffered the consequences of a shrinking economy and been unable to meet his obligations for a period of time (emphasis on unable) will back me up on that.
As far as not putting gear on a credit card if it's a hobby: I have a modest budget for my hobby. I do not want my hobby budget eaten up by the high interest rates of credit cards. That's literally throwing money away when there are zero-interest avenues available. If you're going to pay the credit balance off every billing cycle, then really you can afford to drop the cash on the purchase in the first place and the whole credit question is moot.
I sympathize with the OP in this, the low-end forum, because at least for me, the possibility of home recording opens up new creative avenues for my art, and the cost of admission has come down so drastically that it is within reach on some level for us all...and financing makes it that much more available. And if they didn't have options like that, so many of these companies who have their fingers in the home recording market, including the distributors like AMS or guitarcenter, would be struggling much more in this economy if they couldn't provide these services. I love it, and I wish it extended into other markets. I've been wanting to drop $300 on a digital camera for months, but I never have that much cash on hand at any one moment. So I don't buy it, and the camera store loses a sale.
I hear so many people complain because they were late on a payment and their interest rate was jacked up. It's a contract. You are responsible to honor it down to the dollar. YOU missed the payment. It is clearly spelled out what will happen. Plan ahead before you commit so you can pay your bill online a week before it's due. You have immediate confirmation and a cushion so you are not late with a payment.
Humans make mistakes, forget things. I'm very happy you're so skilled with your money, and certainly wish I had been better with it in my past. I think the posts of "Don't do it, it's not worth it" should probably be reworded to "Unless you've got a real good reason, I wouldn't give myself the chance to screw up that badly over a mic pre." Your point that there's nothing inherently wrong any of these methods is spot on. You just have to make sure you know what you're getting into...