If it didn't matter then the Russians would not have reacted angrily to this. The article in The Independent had one Russian arms manufacturer complaining on how it would affect them meeting potential customers and possible sales.
Will the sanctions stop Putin and Russia from doing something if they are determined to do it, no, but it does provide them with a cost and inconvenience which will affect their economy and Putin's long term prospects as the Russian people will only put up with the dictator if he carries on making them richer and that is his current problem, the economy is tanking, so he is using various foreign adventures with Ukraine and Syria and Russian nationalism to boost his popularity but like a drug it is only a short term fix which has to be repeated.
Putin has made a big miscalculation where he was relying when he sent his terrorists into East Ukraine, that it would trigger a locally backed uprising, but the vast majority of the locals, Russians and Ukrainians don't want anything to do with them. Hence, Putin has tried to reinforce them with increasing amounts of tanks, APC's and AA equipment, with those captured and destroyed by the Ukrainian army having their serial numbers traced back to their Russian manufacturing facilities, which has compromised his plausible deniability cover and his terrorists are still gradually losing where the Ukrainian armed forces have now got their act together. Today, there have been unconfirmed reports of a Russian armoured column creating a 3km wide corridor towards Luhansk. If confirmed this will be a further major escalation.
Yesterday, there were tripartite talks between the EU, Ukraine and Russia in which Russia demanded a permanent veto on the EU / Ukraine free trade agreement implementation if Russia objected to any of the provisions or there are any identified potential negative effects on any imports to Russia through Ukraine. Once the EU and Ukrainian delegations has stopped laughing they politely told Russia to Fff fade away.
Putin has over extended himself in Ukraine where he should have stopped with his Crimea takeover as at least this made some strategic sense, whereas what he is currently doing in east Ukraine doesn't, but he does not have complete control over the terrorists where many are Far-Right ideologically driven nationalists who want to create a new greater Russian empire. This is why when Slavansk fell and some of the terrorists tried to cross back into Russia but they were fired upon by the Russian border guards as Russia doesn't want these potential trouble makers back, but for domestic reasons, he can't be seen to fail. Probably the smartest way out of it at this time is to stop the support of the terrorists in return for Ukraine agreeing to be a neutral country by never joining NATO and also going no further then the current EU trade agreement with their relations and integration with the west. This would probably be politically acceptable to both sizes as Putin would be seen to gain Russian security and it would be enough for the Ukrainian president as it would be political suicide for the him to accept any independence for the Donbas region.