The theory I have seen when they say we should convert into bounds near retirement is that you don't really get to decide when to sell, that's money you need to live. And if you are unlucky enough to need money when there is a market crash, you are screwed.
Bounds are not as volatile, so even if you lose some money from inflation, you are less likely to lose a lot of money, money you need to live, from the whims of the market. You want to protect your capital, yields don't matter as much if you near the end of your life.
If you are younger, and you make reasonable investments and not gambles, you can expect that your value will go up (more so than with bounds) within a decade or two, and because you have income, you don't need that money and you can wait for the market to recover before selling.
Bounds are not as volatile, so even if you lose some money from inflation, you are less likely to lose a lot of money, money you need to live, from the whims of the market. You want to protect your capital, yields don't matter as much if you near the end of your life.
If you are younger, and you make reasonable investments and not gambles, you can expect that your value will go up (more so than with bounds) within a decade or two, and because you have income, you don't need that money and you can wait for the market to recover before selling.