That screen is half year old it happened when Monero was added to Alpha Bay.
Truth is that Darkmarkets use BTC. BTC is currency used on darkmarket. That is a fact and this will not change quite some time. Small part of users that are more privacy oriented use Monero.
Reasons for that are simple. You can see from that screen, that Battalion guy have no ideas how to prove his transaction. If you dont educate yourself is better to stay on what you allready know to use. Like i will not go write here in German altho i should know at least a bit, because I can write way better in English. If somehow Teymos forbid English here, i will force myself to learn German more and write only in German.

Monero is here for those that want to use it. It is not for anyone else.