I have never used cash out before, I just don't see the point. I often place small bets, and if I lose it's not a problem for me, but if I win it can be a big win, so I don't think about taking my money before the end of the match. And sometimes it happens that a team can score even in extra time, so I don't see the point in canceling a bet that could be a winning one. Maybe if I placed big bets I would rate this feature differently.
Do you follow the game you have placed a bet? If there was a case, when you have placed a bet before game has started (lets take football as example), and you see that your team is losing 0:3 but there is a period still to play, then you would leave your bet as it is ? If you believe in extra time miracles, why not cash out obviously losing bet, and bet on the same team again, as odds will be very tempting/different.
Some math. You place $10 on team 1 with 1.5 odd. Your team start to lose 0:3. You could cash-out for example $3, and place them on team 1 with +5 odd (or higher, I dont know, with such score gap odds might be even +10). So you either lose your $10 anyway, or instead of winnings $15, get $15+ as odds are much higher the more score gap is, the amount of time left is.