Perhaps you are seeking why an investor might use a trust rather than an LLC...I can't see another reason for you writing such a post but I can answer this one.....LLC's are under the IRS rules of corporations....we know that 'income' is defined as 'corporate profits.' So, the IRS requires that ALL corporations must file a special and distinct tax return for each corporation.
This humble guy asks the question, why would one want to have one additional interaction with such an organization where we know they are aggressive, they use threat coercion and force, and they routinely break most laws to get their ways.
Having said all that, I, personally, have read 'private letter rulings' issued by the IRS which says that a Trust is NOT required to have a special and distinct tax return for that trust entity.
So, if you do what you would normally do with your personal taxes, one might operate their business and/or property inside of a trust for at least one great reason; and that is so the owner would not have one additional exposure to such an aggressive organization each year.
IN addition, the trust entity can offer the owner the same safety measures of limited liability, privacy, etc. that a corporation offers.
Hope this helps.
Rob