Opportunistic interjection that unnecessary ${} is the most bothersome style choice in any language I know of:

- It obscures actual uses of modifiers, particularly ${foo-} when set -u is in effect,

- It's obvious when a name runs into subsequent text, even if one has somehow avoided syntax highlighting,

- And expansions followed by identifier chars don't actually occur in practice. Cases where the quotes cannot be moved to surround the variable are often interpolation of an argument to echo, whose behaviour is such a mess not even portable between bash and dash that shellcheck ought to be demanding printf at all times instead!