While Bitcoin is really bad as SoV currently, most of the arguments towards Bitcoin are always focused on the present(e.g. low tps, expensive to transact, volatile), completely ignoring the potential liquidity improvement by time and the potential development that could improve the technology in general in the future.
It also comes to how the Bitcoiners phrase it. They should be saying "Bitcoin could potentially be a great global SoV in the future" than just "Bitcoin is a good SoV".
Bitcoin is not bad as store of value at all, it just depends on your own entry point, which also applies to Gold. Gold hasn't really been that much of a store of value if you measure from peak to where it is today, which is the same reason people consider Bitcoin a bad store of value today. It all depends on your entry point and how you read the charts.
Bitcoin is a bad store of value when you after whatever period of time have lost value, and then still, it's your entry point that made you lose.
In the end low transaction throughput is meaningless when you see that the high transaction throughput coins don't experience much use at all outside speculation.