Renting/leasing is often more cash flow friendly in the short/near term (due to not needing large sums of initial investment and [in the U.S.] tax implications of OpEx vs CapEx expenditures)
If you're trying to preserve capital in a start-up situation renting/leasing is the way to go until you know what resources you actually need.
You can't get rid of a 1+ year lease agreement, or something that you purchased. Nor is it a good idea to buy/lease more quickly without really thinking about the long-term financials.
Once the business fundamentals (profitability/cost savings), load profile, and your team's skills can support physical infrastructure, it makes sense to do so. Until then, virtualize!
2) Well... yes. My entire premise is based upon not making any long-term leases/purchases, as I stated. Hence, if you bought a 1 year reserved instance, you're doing long-term leasing, and therefore your situation doesn't fall into what I was discussing. So, I'm not sure what your point is.