The extra 10% would be split up as 6% max as seller concessions towards closing costs, then the remaining 4% would come off the principal loan amount. 

That will cost extra time and money to remedy.

The product is available but the pricing is not as pretty by any means, you’ll be looking at a rate 1-1.5% higher and possibly an extra .5-1 point in cost right off the bat. 

While they may not care much about the neighborhood aesthetics, highlighting the potential for legal issues or fines due to the environmental hazards might get their attention.

Experience with STRs - they at least know or can understand the extra steps it takes to make ready the properties, including photos (cleaners hate taking photos, I've found, even though it protects them from being blamed)2.

He told me that given that I was still fairly new to investing (5 years) that I should consider the benefits of having the extra cash on hand either for emergencies or for future down payments on additional properties.

They are much safer, less error prone, cleaner, and aesthetically pleasing.

People have very short attention spans now, and making them jump one extra hoop to book your home is an additional hurdle you do not need. 

Is it worth that extra 5% in efficiency?

@Jessica CotéHouse hacking involves transforming a carriage house into a long-term rental for landlord experience and extra revenue.