I would prefer if the Primal app was the signer. Supporting external signers would still be a great feature.
Discussion
Me too, I would prefer if nsec.app was the signer, I must be honest with you guys, it feels much safer instead of typing your NSEC everytime you want to sign in to Primal; device keyboards store your entire input history.
I would worry about securing my NSEC in a PWA.
You could include your nsec, npub and nsec.app password in your seedphrase backup. By stamping the words and number sequences on a flat metal base, the inscriptions become deep and visible, you can include a depth color and you can change the color of stainless steel (i.e. gold or carbon blue), with a simple gas stove or blow torch, WITHOUT damaging the inscriptions.
26 washers - 12 for seedphrase and password, 12 for nsec, npub and nsec.app password, I managed to fit all sequences in 12 washers by using front and back of the washers. 2 washers are for privacy cover.
It's a work in progress and you will probably make many of these once you purchase the right tools.