No DSG’s I’ve driven have it, although most have had the option to use a manual mode.
I have a honda civic now and it has a CVT but no B just D and S but luckily being the sport it has the flappy paddles so you can use them to select Higher engine revs and stop the car dropping the revs, like it’s into a higher gear (which a cvt don’t really have gears) which is often a big issue in the sense modern cars always try to keep the revs as low as possible and kicking down with the gas peddle don’t help at all in that situation.
I guess as soon as you take your foot off the gas it starts to slow down or detects an incline i do not know exactly.. Like hill start assist somehow it knows, where as brake assist works all the time. if you got the button selected that is and ya seat belt on etc..