ok, so:

1) there is no “digital bitcoin” money. no blockchain of each coin floating around from “wallet” to “wallet.” there is only a ledger recording transactions.

2) however, in order to record the transaction there has to be a digital “address” or location or identity encoded. an association. this is what you/all refer to as a “key”? no: there is first an address or location (you are calling this a “safe deposit box”) & then there is the “key” which is essentially authority to transact. Transact is publishing a new location of amount/s to the bitcoin ledger.

What you are calling “wallet” is the location (safe deposit) but really is an association or link of the amount on the ledger to a unique code (address/identity/location/safe deposit) & “key” is authority to transact or publish a new location of said amount/s associated to that code to the bitcoin ledger?

When people are “purchasing” “bitcoin” they are purchasing the right to publish or disperse encoded/linked/associative amounts & destinations of new associations to the ledger? Trying to understand what people are buying, what a wallet is, and what a key is ACTUALLY.