As we can see it right now its not affected at all, the prices are indeed cheaper on here and another fact is that on steam its not something that is very known for accepting the bitcoin.
I think a lot of people do not even know this..
Not only that,most of the steam users buy funds from 3rd party sites or from other users,they don't actully purchase funds from steam directly and that is one of the reasons that we didnt see a big bump in the price
Well, as far as I remember correctly Steam acceptance happened in April. Bitcoin price was around $~430 back then.
And then price skyrocketed to $700 in June - sure it was probably mostly to incoming Halving but we can't be sure that Steam factor played a role there.