This is why buying and holding bitcoin for decades could be called anything, long term investment, asset, currency, whatever. I believe it is one of the best out there and I am one of those people who call it an asset and I am not planning on selling it anytime soon.
Honestly, you have made a mistake by holding onto your bitcoin for so many years without ever spending it. I believe this is one of the biggest mistakes if you aim for mass adoption. If you do not get the economy going, holding onto it will be of no use. Nakamoto's true philosophy was to create a currency that would free us from the financial system, but this cannot be achieved if you hold it as an asset.