this is a big scam, because it is much safer to buy real bitcoin compared to this bitcoin etf considering that it is centralized and prone to manipulation.
It is good if you choose to be your own custodian and don't buy Bitcoin Spot ETF shares and rely on third party custodians.
It's your Bitcoin private key, it's your bitcoins, you are custodian of your own Bitcoin bank. It's good.
I really don't know Bitcoin Spot ETFs are scam because they actually have to use money to buy bitcoins. Their Bitcoin treasuries are tracked and under regulations of governments. They can not do shady things like don't use money to buy bitcoins but create shares for sales to customers.
I'm not sure how much of a scam it is in the true sense of the word, but I think the appeal to most investors (those who aren't crypto- or tech-savvy at least) is that it's easier to just buy shares in an ETF than it is to use a crypto exchange that they might not be familiar with or true, and they don't have to worry about keeping their own bitcoin safe.
It will help Bitcoin adoption because Bitcoin Spot ETFs actually bring more people to Bitcoin world. They bring more capital to Bitcoin market and with more supply, more capital, price will have to rise.
Price might not rise immediately but with time and with sustainable increasing capital in this market, price must price higher.