That was how it was at the start, but the bookies have caught on and you now have to "rollover" the bonus, which essentially means you have to make several more bets which cancel each other out, each time eating away at the bonus you get, before you can withdraw the cash. Ends up making every bonus more time-consuming and ultimately less profitable.
Essentially, yes - that is the case... But only if you do matched betting by hand as it's slightly more complicated and the calculations can be more complex.
If you do it automatically like I do, then it's far less hassle as it's based on a set process - it's literally follow the instructions and with draw..