Recently I learned of a new way to express potential form. Here's a few example sentences:
The second example I put for contrast, because it illustrates one obvious difference which is that I don't think potential forms of ある and いる exist.
In the first example, however, it's not so clear. Instinctually, from looking at these and a few other examples, I think perhaps there is a sense of impossibility here that is not present in simple できる or ～られる form, but I have trouble articulating it, and it may be a red herring anyway.
For example, change the first sentence to this:
Does it have a different nuance now?
Can someone elaborate on the differences between these two constructs?