Good point on the appearance of zoysia when grown under an irrigation deficit. It won't die, but it sure looks bad. Take it far enough and you are now faced with a thinned out lawn that will take a very long time to grow back. The worst looking zoysia I have seen was in partial shade growing under irrigation deficit conditions. Thin, pale and just butt ugly. Mowing height had something to do with that as well. Zoysia kept at fairway height with a reel does not lose as much water as the same grass cut crudely and high with a rotary. Less leaf area=less water loss.
The high growth rate and availability as seed works in the favor of bermuda for areas subject to physical damage. There is also the option of frying an area and starting over from seed if the weeds get away.
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Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738