A lot of smartphones, laptops, and computers use gold in their connections.
Yes, but it isn't the only thing it can be used for. As said, things might move a bit slower and astronauts won't have quite as good radiation protection, but there are alternatives for gold - I don't think that there is anything that relies only on gold, is there? I didn't even consider the value of jewellery, as that is useless as it is :)
There are much smaller options, and even coins, so it isn't as unwieldly as you think.
Coins printed with the "dollar value" as legal tender are the most efficient - as if you notice, you can only carry something like "10K in cash" through an airport. that is 10,000 gold dollar coins - worth a few million.
But as we have seen, the law would mean very little at that point, wouldn't it?