Well it's simple. You don't want to miss a sudden spike of high BTC prices cuz it was 2 hours long and you were at work when it happened. You also don't want to set all your BTC to sell at $15 and then it turns out the spike was to $17 and you could have made more.
So waaaaaaay back in the day when I had a lot of BTC, at almost all times I had a sales order for 10BTC at $8.50, 10BTC at $9.00, 10BTC at $9.50, and 10BTC at $10.00 just in case. That way I make money on a small spike, I make money on a big spike, and I don't lose anything if the price falls. I actually had tiered buying orders too so I made money from a price drop as well, lol.
Quite a few people do that btw. Way back when, there was a rich person on one of the exchanges was always leaving 200BC orders in like 8 steps. They'd move them around but they were always there.
Let me guess, you also have a modified Martingale betting system that makes money on Satoshi Dice?
Just kidding around. Sure, that strategy works fine if you can predict the day-to-day range of trading rate better than average.