A temporary market imbalance, combined with cheap borrowing costs (ultra-low interest rates). 

I do some that aren't, but have that in mind that you will be selling for cash, seller financing or on a much higher rate with a mobile home specific lender (higher rates).

If the cap rate is breaking even or above interest rates it most likely would make sense, taking into account that in five year period interest rate have a higher possibility of coming down than going up. 

I found out that the seller is very motivated and is offering ALL types of creative financing options with rates as low as 3.75%.

Terms are usually 5-10 years fully amortizing in the low-mid teen's on average.They are basically taking a pledge against your future cash flows, similar to an MCA, but with rates from 11-16% fully amortizing on 5-10 yr terms, so payments are not nearly as ugly as an MCA, but similar concept.If they're a TPO or Broker for the same company, the program could be real.

Low closing costs, with minimal documentation and competitive rates.

It will appreciate because that is what prices are saying and if or when they lower the interest rates the prices of the houses will go up.

I’ve noticed that credit unions tend to have slightly better interest rates since they typically are not for profit whereas a normal bank or broker is.

Theirs an initial withdraw rate and a standard rate everytime you use it.

Low closing costs, with minimal documentation and competitive rates.