It allows you to buy properties for less, because of their condition, improve their value, attract better tenants and create equity in the process.

Up to 70% LTV on multi-unit investments is common and will have the most attractive rates, but there are options above that at slightly higher rates....and assuming the money is going to good use, then perhaps worth considering.  

However, I've also got over a million in real estate either listed, to-be-listed, or under contract, and a quarter million dollar budget after we sell a rehab to go flip and BRRRR properties myself. 

Plus, where my current bank would only finance me for maximum 6 rental properties, this new bank would finance me for up to 8 millions.

@Jeremy DockendorfI fail to see how this seller financing is attractive (to you) for a primary residence.I also don't know why you think a seller would agree to tie up the property in a contingency situation when he/she could leave it on the open market and get cash.

It’s a heavier lift for me to come up with the 25% down, which is why option A is so attractive.  

For an investor to be an attractive option to a lender you need to present yourself as a low risk investment to them.

I was once told a story of a guy who bought a piece of plywood for his roofer and got sued for millions when one of his roofers workers died on the job.

Many are attracted to the "up and comming" neighborhoods, some of which have been up and comming for 20 years.

New mortgage brokers often will not have the experience and not have built up a portfolio of lenders they know will close the deal and not re-trade mid deal.My capital markets brokers close hundreds of millions a year in loans.