For a relatively long time? I'd agree with you. In those instances you should only leave small amounts to for example leverage our lightning capabilities to pay for every-day goods.

However the success of more traditional mixers has shown us that there is definitely a demand for mixing moderate to large amounts of funds by means of a custodial, centralized third-party (= traditional mixer). You can do exactly that by swapping back your "giftcards" (unblinded coins) shortly after receiving them, with the speed of a database query.

So really, there would be no difference between us and any other custodial, centralized mixer. If you think about it this is also exactly what you are doing with more "traditional" mixers: you're swapping real** bitcoins for a promise of future** bitcoins.

blindmixer is really no different just because we have packaged it in a more sophisticated way. you swap real bitcoins for giftcards (a promise to future bitcoins), and you can immediately at will converse those back to real bitcoins.

Now the "useful applications" for doing such an operation are listed in the OP and follow from what traditional mixers offer but blindmixer also offers (and perhaps negates) some features such as:
A. being able to choose how to "swap out" these funds (lightning or regular txs)
B. Added proveable* privacy. The most prominent feature is that these giftcards are blinded, and as such we don't know which "promise" belongs to you so to speak. * The degree in which this privacy is acquired is largely dependant on how you use us. This applies to both the on-chain vector and the custodian vector.

Let me also just repeat that the giftcard itself is signed by the custodian using the corresponding public key (depending on the magnitude). Now the giftcard or "coin" is nothing more than a public key and so you use the corresponding private key to prove ownership when conversing it back to real bitcoins, leaving little to no room for the custodian to scam you as an individual without it being proveable.


future* = no matter how short, can be five minutes or a day.
real* = bitcoins only you have the private key to.