Similarly you can argue that being aware of ego depletion will allow people to work with it better - after e.g. mentally exhausting work it's better to avoid going to grocery store because it will be more difficult than usual to resist buying sweets / junk food etc. Instead postpone it to tomorrow when you are "fully charged" again. By being aware of ego depletion (assuming it's true), you can actually optimize your life better.
It's quite controversial in the real world where "each service class has an interface" is official codified dogma.
OTOH in certain specific cases I see the value of the interface even for just one class when I want to clearly separate the contract (which I'm bound to fulfill now and in the future) and the implementation specific comments.
Let's say that in my little pet programming language I have just one List type. I want to clearly separate what's the contract (indexed ordered sequence) as opposed to "incidental" implementation details (constant cost random index access).