The difference being that companies are meant to be trying to make money and give that to their investors, whereas cryptocoins are nothing but a string of numbers.

I agree having a company trying to produce revenue is arguably more valuable, but keep in mind cryptocurrency isn't _just_ a string of numbers -- what you're buying into is a massive network of machines verifying your transactions and protecting the system from things like double-spends. Sure, Bitcoin has scaling issues, but there is still an insane amount of computing power backing it, and that isn't changing. I'm not 100% sure I see as much value in Ethereum, for sure -- since throwing that much computing power at verifying programs is more dubious to me, as is the switch to proof of stake.

Ethereum does the same thing as Bitcoin. It's just that you can also have scripts on the network that move money around.

That's as much a liability as it is an asset -- for instance, https://www.reddit.com/r/ethereum/comments/6eruqb/if_your_ex... ("QuadrigaCX exchange lost 60000 Ether due to smart contract problems").

You have to be careful, but people have gotten a lot better at being careful. The contract used by QuadrigaCX was written last summer, and violated a well-known best practice, which is no longer necessary due to an improvement in Solidity. Human error is always a problem, but these days it's common to hire at least one security auditor for any contract that handles nontrivial amounts of money. (I'm a full-time Solidity dev/auditor.)

It's still a little scary, but I'd say it's less scary than safety-critical embedded code.

Gold doesn't make money either. Gold isn't as valuable as a commodity for engineering (what's it's actually useful for) as the markets sets its price at.

Gold, like fiat currency, like "cryptocoins" are all just stores of value that a market sets a value to.

Sure, except with gold, you could buy a nice suit and steak dinner in any era.

Because a market decided that it is valuable. Same with crypto.