Versus fiat Monero is doing just fine. Not as well as Bitcoin, but a steady upward trend in price over the long run.

Ultimately SoV is speculation. The future is never 100% certain. If you think Bitcoins historical price trend will continue, just use Bitcoin to save long term, while having a small stack of Monero for spending (cheap, untraceable, anonymous, and private). How small that is depends how often you use it. If someone doesn't really transact with crypto, then I can understand why they might not have any use for Monero.