is this kind of manipulation can work both ways for buying and seeling and for all currencies can anybody tell me ?
They are manipulating alts and they have their own intention of pumping their own coin, yovi and yob2x that aren't even showing up when you will search it on CMC.
Crazy pumps are happening to there just take a look for a couple of minutes and you'll see an alt rising 400%+ within a split second and will be dumped later on.
an other thing.. for exemple is the benefits of selling a currency for BTC is the same if i sell it for USD ? hope it isn't a dumb question thank you guys
They have the tabs for it, TOP, BTC, ETH, DOGE, WAVES, USD, RUR. But while it's early, consider other good exchange instead of them.