What? If the stock goes lower than the strike price, the downside on a naked put is the difference between strike price and market price. You will be forced to take delivery of the stock at the strike price when you could have bought it for market price if you hadn't written the option.

It is not 0.

I suggest most retail to be short straddles against a core underlying position for yield enhancement. Yes, over a number of decades you will have something go against you, but under the current monetary and fiscal regimes, you should be hoping for the day that you can buy the dip or sell the rip via a systemic short vol overlay.

Selling straddles or strangles against a long position in a stock that you do like is reasonable play, but there needs to be a full understanding of how vol and time decay can effect the value of the entire position up to maturity and a recognition that nobody is getting assigned/called early excepting unique circumstances (ie, high dividend stocks)

For those reasons, I'd only suggest these types of trades to fairly well capitalized retail investors and those who have taken the time to gain a basic understanding of equity options and the use of margin. In proper hands, these can be very rewarding trade ideas/techniques.

So "people should buy a 20-30% dip" but should not be invested already? Because if they are, selling puts may not be a good idea.

That does not preculde already being invested as sitting on the sidelines waiting for such a move can be self defeating (the market rises 50% then drops 30% dramatically you would still be better off to have bought day one).

If you sell puts and are assigned, it may or may not happen at the optimal post crash price, but you will still be adding to your long at a much lower level. For instance, you sell a 30 put when the market is at 45. There is a great sell off, you are assigned when the underlying is trading at 25. You own at 30 less whatever premium you received, likely above 25. Certainly not the end of the world, but investor psychology is such that some people will be upset after the fact if they are paying more than current market price.

However, if you are not assigned you'll be pocketing those premiums as added income. But that is also another risk with naked puts - the market sells off but well before expiration and then rises again. You would miss the chance to buy unless you make the decision to take back the short puts at a loss and buy the cash at the now lower price. Again, you'll likely be paying net more than just having parked the cash and waited.

So naked puts may not be the best strategy if you know you absolutely positively will want to buy at a certain price, no matter what.

It may make sense if you had dry powder waiting for a correction. But at that point you are forced to buy (and as you say it may be at a higher price that the prevailing one in the market). You get premiums but you lose flexibility.

The problem is that they may be willing to own at a lower level today. But it may happen that when they have to own it the price is lower for a good reason.