*some kind words deleted*
There are always various threats to bitcoin, and off the top of my head (which also might well be really inaccurate), I would consider that probably the kinds of threats that relate to having to use third parties to transact in bitcoin are probably amongst the worst of threats, and so it seems to me that ongoingly many of us need to be trying to figure out ways to transact directly with others in bitcoin even if there might be ongoing attempts to get us to transact through third party intermediaries.
Surely i have no problem conceding that you might recognize and appreciate some bitcoin threats that I am not quite recognizing and appreciating.. so there is that aspect too.
I see two major fronts on which bitcoin has some upcoming challenges. These two things overlap and also are not new at all. But the part that is new is the audience for them. Your example really encapsulates them both.
1. Scaling. This is currently a contiuum with different amounts of two tradeoffs.
a. complexity - systems that use complex schemes to retain trust minimization
b. trust - systems that return trust to a third party for ease and cheapness of use
"A" is hard. And so far there are not many systems that are using it. Lightning is the best example of a scheme that retains the trust minimization of the base layer. But lightning's complexity makes it hard for the individual user. Interestingly it is being used best by professional nodes like LSPs, Exchanges, and more recently as the backbone for hybrid trust model wallets. The latter is one of the most interesting developments currently.
"B" is easy. Especially full trust.
Cashu is a great example of the second tradeoff. And though the tech itself is fantastic (Chaumian mints) and super easy to use, allows strong privacy, and is a bearer asset I think it is one of the worst sets of tradeoffs available for users who care at ALL about sovereignty. It relies on a single point of failure. A single mint. Essentially the e-cash token is a simple IOU. NYKNYC. Not only that but the issuer can "claw back" the value selectively.

And the "plebs" are gobbling this up like it's sliced bread. Very very worrisome to me, honestly.
This pleb never heard of Cashu, so I gather, it is not THAT wide spread yet.
My aim with any wallet/provider/bitcoin bank is one and the same;
I am interested in a solution what would, in a programmed, decentralized fashion, allow me to lend my bitcoin (without releasing it's custody) to a third partly, that would also be programmatically controlled, so I get , say 1-3% "interest" on my bitcoin...in bitcoin, NOT $$. Whoever achieves this is a winner in my "book". I don't want to spend bitcoin because it is hard to replace, but I surely would like to have some income off of it.
If it is an asset, it should or could behave like an asset. Even Satoshi envisioned "bitcoin banks".
Who could be a consumer of such lending-mostly margin players, which are plenty, some institutions, who want an edge, entrepreneurs looking for a short term loan, etc.
I think Blockstream is trying something along these lines, but they are not there yet, afaik.
This summer, there are supposed to be some bills passed about "digital market structure' as they can't just say it is bitcoin only.
We shall see afterwards.