Because there is no black and white answer if you qualify as a trader. If you don't elect MTM, the benefits are minimal. One such benefit is Home Office. There is no black and white for that either. For many the risk and hassle of it is not worth the benefit. And Robert Morse is completely wrong.
No they are not. As a "trader in securities" you can claim all your expenses on schedule C just like a regular business would. What's even better is you don't even have to pay self-employment taxes i.e FICA. As someone previously said, you don't have to elect MTM to enjoy business expensing. https://www.irs.gov/taxtopics/tc429
I think one can avoid considering tax status and avoid keeping trade records for tax preparer (IRS) if he simply trades his IRA account. Correct me if that sounds wrong.
that is correct. The only problem is that you are trading out of an IRA account and have to pay a 10% early withdrawal penalty if you touch it before 59 1/2 YO. IMO it would be best used as an "investment" account rather than "trading" but I think one's age is a major factor in that decision.
There are really just two categories aren't there? Professional and otherwise. If your profession, according to the IRS rules, is buying and selling securities, wouldn't you opt to use MTM accounting? I don't understand why you wouldn't. What am I missing?