Coinbase hits top spot on Apple's US App Store despite struggling to handle bitcoin demand

Ignoring recent price rises for a second, if you can — there’s no greater sign of bitcoin fever than an app that lets you buy the cryptocurrency becoming the most downloaded app in the App Store. That’s exactly what happened on Thursday when Coinbase, the $1.6-billion-valued company behind what is arguably the world’s best-known exchange for converting fiat into…