So far most of the comments in this thread have been about Fund & Grow's performance in gaining personal credit for their clients. Remember that a major part of their pitch is to get a line of business credit - credit that is unsecured and invisible on the client's personal credit rating.
My curiosity was aroused when the OP stated that Fund & Grow was applying for business credit for him before he has a LLC . To get any meaningful line of business credit a business needs a track record or some pretty hefty assets. Obviously Fund & Grow has a method to sidestep the credit department's underwriting standards.
My theory is that they are making use of " shelf corporations ", corporations with no assets or current business activity. A couple of minutes ago I checked Google and easily found a site that offered such corporations for sale for a one time fee of between $700 and $5000 depending on the date of incorporation. They promise paprs of incorporation, minutes of board meetings, a company seal... basically a business in a can. The salient point is that it is a pre-aged business that will get serious consideration from the card issuer.
This is just a theory, but if I am correct the $4000 fee is not only buying you a credit limit, it is buying you a business. Well...sort of.