Its utility is similar to that of cash. But unlike cash it's (1) less fungible (2) much easier to transport (3) harder to secure from theft and/or destruction * (4) value is more volatile than USD/EUR/CAD/AUD (5) incredibly resource intensive to maintain (and growing!).

It's not an equity, it's a currency.

The Bitcoin network is nigh "indestructible" as long as some folks still consider it useful. This delivers credibility towards the faith required to support some value. If its value dropped by 99% tomorrow (maybe from aggressive global legislation and cooperation among governments), it would still function (but perhaps primarily maintained by sanctioned countries).

I think there's significant pros and cons to cryptocurrency in general and Bitcoin specifically. As the emission rate continues to decrease, I suspect its value will stay relatively high relative to what it is now.

EDIT: I said in (3) above that it's harder to secure bitcoin from destruction (than cash) but in some ways it's remarkably more robust than cash. You can make as many copies of the keys securing your bitcoins as you like (and/or use multi-sig). Your home burning down would destroy cash, but if you have a backup your bitcoins are preserved. However this is in tension with "secure from theft".