The downside of real estate ETFs is you don't see the mortgage interest deduction which can decrease the house payments by ~20% (depending on tax bracket).
Again, if your interest is in profit, real estate-related investments are hard to beat for the average person, especially if you hold them in tax advantaged retirement accounts. Also, consider that with a leveraged product like MORL, which has total annual fees of .80%, you're leveraging at an effective cost of capital you could never get as an individual.
As an example, for a programmer in a ~37% tax bracket owning a million dollar home in the Silicon Valley, you could be talking about a tax-deduction on the order of $12k annually.
With that said, MORL looks like a very interesting product -- and probably a better investment than a house for most people.
The great thing about a self-directed solo 401(k) is that you can purchase physical real estate in the retirement (speak to qualified counsel about the rules). Also, if you want to buy a home, you can borrow up to half of your 401(k) balance (to use as a down payment) and, if your plan allows, the repayment term for a loan used to purchase a primary residence can typically be extended beyond five years (the typical term).