A lot of investors see the risk/reward calculation and they decide to go ahead with it.

If you're willing to buy, hold, and benefit from long-term appreciation (5-7+ years), you'll reap the financial rewards.

Not entirely, If you buy in a " bad area but pay correctly it can be very rewarding.

Now if I was asking them to flog a problem for me, I'll reward for their efforts.

You can open a business credit card in your name (better rewards usually) to keep expenses separate.

David Lichtenstadter yes you can, NJ has not recover fully like NY so the rewards are unlimited

It really has been one of the most rewarding moments of my 26 years of life and as an Asian with high expectation parents, I was glad I had something to prove my worth to them.

Higher risk market may have stagnation on those fronts or more volatility in asset price.The proper strategy in DC is to hold long term, and if one does they will be handsomely rewarded with asset and rent growth.

We would consider renting out the basement on the weekends as an air bnb but we would need to weigh up the effort vs rewards there to see if it will be worth it. 

All that said, I have found the experience to be extremely rewarding, both personally and professionally, and the satisfaction that comes from helping my clients understand their homes and navigate the defects discovered makes it all worthwhile (One of my inspections just saved a client $42K on their deal price!)