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?
Modern electronics, gadgets, vehicles, and Space equipment NEED to use gold. Sure there are alternatives like silver and copper, but they corrode easily and are not dependable. When you need security, dependability and quality, gold is necessary. With space equipment, where any problems or replacement would require millions/billions of dollars, there is no alternative. I find it concerning that you think astronauts not having quite as good radiation protection is a minor thing.
I don't really know why you suddenly brought up dollar value tokens as legal tender, as well as why you would even bring them through the airport, when we were just talking about them as physical investment. Do you print your stock certificates and bring them with you all the time? haha.