Investing is Widespread now in the Society such that the Inability of not Investing, is Paving a room for not Benefitting from the Outcome.
And Right now Investing in Crypto is a yardstick of measurement and has created an opportunity that's reliable and trusted..
But I really can't tell how thus Investing in The Economy will help one's Country.
Investing is important for a country to advance and not stand still. It's very similar to a company that needs to invest in itself to not become obsolete. There are different forms of investing that will bring different outcomes. A country can invest in it's infrastructure to make it more competitive international. For example, having good Internet access is a must today. Without it there is almost no chance of running a business, same goes for security. Another form of investing is into knowledge, having better schools and universities makes sure that the population will be more intelligent in the long run. If a country doesn't invest into education than it will be hard to replace the workforce when older employees go in retirement. Also innovation requires investing.
I don't think OP asked about a country investing on to something, its seems how it can be useful for a country when someone invest their money there. Certainly the funds are incoming so it can generate more money and also good relationship if its from foreign companies because tax is what very important for a company so no country will deny the funds coming to them.