For me, the "fact" that bitcoin transaction is instant is a partial "truth". In fact, the confirmation time is about 10 minutes and during the so-called stress tests it will become longer.
This is both true and not true, in a sense. For small transactions, say in a cafe, you would be paying instantly (and it will be accepted as such). But, of course, we all know it's not technically confirmed until the 10 minute period that the block is added. Anything with a fee will also be completely overlooked for a while.
Care to explain the last part "Anything with a fee will also be completely overlooked for a while."?
Do you mean, everything without a fee will be overlooked for a while?
In reality, transactions with big fees will probably be included in the next block, transactions with small fees will probably eventually be added, and transactions without a fee are probably not even accepted by the nodes (let alone, added to a block)