Yobit controls when they stop supporting a coin, and Yobit knows that this will hurt many of its investors. Without any moral conviction they will move onto their next token, and promote that with 10% interest, and the whole process starts again. They'll continue supporting it until they believe it'll earn more by promoting a new, and exciting token. Investors will try to jump in early this time because they know the coin will be dropped eventually, and investors will be looking to get rid of the coin until it eventually reaches 1 satoshi, and no one buys it.
Any investor who sees an instrument / scheme / crypto is offering 10% daily should be responsible enough to walk away knowing that such an interest rate cannot be mathematically sustained without total devaluation of the traded product...
On the other hand, offering interest rates for BTC holdings is a legitimate benefit, which the invest box also seems to provide, and no one has come forward in years that Yobit has stolen from the accounts or anything criminal like that; thus the exchange's continued popularity...
Not to mention there are free coins and various other bonuses offered by Yobit, obviously other promotional tactics to market their brand...
It shouldn't be a categorical offense to promote an exchange that is providing some valid services, simply because some other fringe products it offers are highly likely to lead to investors losing money...