The fact that you can buy investments with money makes it a medium of exchange. Money is theoretically supposed to be a store of value as well, but it is not a good store of wealth, due to inflation. With current central bank policy (or at least Fed policy in the US), most interest bearing accounts are not currently a good way to store wealth, because after adjusting for inflation, their low interest rates mean that you are actually losing wealth over time.
> Money is theoretically supposed to be a store of value as well, but it is not a good store of wealth, due to inflation.
Medium of exchange and store of value are the two main functions that "money", as such, can have, but it is misleading to say that money is "theoretically supposed" to serve both purposes. Any particular money is adopted with very specific purposes, and modern fiat money by design has a very limited role as a store of value, being intended primarily as a medium of exchange that is useful as store of value only in the short term (and only secondarily so, as utility as a short-term store of value is essential to utility as a medium of exchange) specifically in order to encourage investment in productive non-money assets as a store of value.
If you put money in a bank, and get interest, it is a store of value just as much as a bond is. It's not a permanent store of value (inflation, etc) but nothing is. Houses can get taken away in floods, bonds can also get wiped out by inflation, and companies can go kaput.
