>What makes an investment in 'this Bitcoin crap' any different from an investment in say Facebook shares or Snap shares? Aren't they just unnecessary digital crap too that nobody actually needs?
There's a fundamental difference between buying shares of a publicly traded company on a regulated exchange and investing in bitcoin. This is quite literally comparing apples and oranges - your examples are not only different in kind, but in purpose. Also, there is a large, rather well funded government institution who aggressively works to make sure the stock market isn't subject to the sorts of abject manipulation, ponzi schemes, and other such unsavoriness that Bitcoin has been subject to. (Side note - watching the Bitcoin market is like watching the last 150 years of finance happen in 2-3 years. It's an interesting object lesson in market manipulation and why the SEC maybe isn't a bad thing).
As to Facebook/Snap being digital crap no one needs - yes. However, just because there's no physical good being created doesn't mean their value is entirely ephemeral/a financial illusion. Facebook/Snap create value by solving a problem people are willing to spend money to solve. Bitcoin creates value by...well it doesn't yet. People invest because they hope that "there'll be huge growth in the area of blockchain technology and tokenised digital assets in the years to come." That's a nice thought, but it's an assumption.
>If Bitcoin remains the gold standard for crypto then it's value will rise accordingly.
It's funny that you mention the gold standard, a standard that was dropped because of its votility, the fact that it was subject to manipulation, and the fact that it benefited some segments of the market FAR more than other.
>...many people invest on the basis that there'll be huge growth in the area of blockchain technology and tokenised digital assets in the years to come.
I think this is undeniably true. However, I think the assumption that bitcoin will be the vehicle for this growth is incorrect, or more charitably, overly optimistic. Bitcoin has accrued a lot of non-technical overhead that I think will prevent it from being used to drive these solutions - things like its association with speculation, the fact that the majority of miners are on the Chinese mainland, etc. I think the growth in blockchain technology will come from companies and individuals taking the concepts of the blockchain and using them to build products with real value (as in, they solve a problem that someone is willing to pay money to have solved). Bitcoin's value (sadly) doesn't come from the technology, which is fascinating and interesting - it comes from the fact that it's created an unregulated market with no barriers to access, which has allowed rampant speculation, incessant hype about 'the technology of the future', and a continual influx of new money to create 'value' that ultimately, has no real value.