As I see to coin market cap, yes the increase of bitcoin leads to increase in all alt coins,
But the ratio of increase in bit coin is smaller comparing to the rise ratio in other Altcoins.
So, Ether and some other Altcoins like Steem usually increases more in its percentage.
I think the reason that more people have to buy Bitcoin first before they can exchange to steem for example.
On the other hand, the drop in USD / Euro also shows an extra untrue / underestimated value of BTC , and hence, in correlated ALTC; which will be back again after USD get stronger again ( but of course this is not a very huge influence , but has to be considered I think.
Don't forget the news about Russia will help BTC and Ether . Besides, the Saudi Arabia accepts the Chinese Yuan instead of USD to exchange their oil with china ( sell the rumour vs. buying the news).
I think most crypto currencies will face a little fall in price next week ( to return back to the their actual true value) .. so I will take a rest this week and will not buy more digital token until actual value ( lower prices) return back may be in a week . Then buy before price correction up again. So, I keep my eyes open ..watching my expectations! I am not an expert, but it's just my common-logic sense :)
I would appreciate your opinions - what do you think guys?