Regardless of whether a snap is only used internally, or whether it is private or not, since a publisher can easily make it public or once it is public, any user can install it, then the same process has to be followed regarding reviews.
Some things to know - the use of browser-support with daemon grants a lot of privileges to a snap (see the previous discussions for similar requests a few years ago for some background on this Suppress the security-snap-v2_daemon_with_browser-support warning for the snap, Request for daemon + browser-support for krellian-kiosk).
Does pcds-kiosk absolutely require the use of browser-support? I understand the wish for daemon is to have long-lived daemon that is automatically started etc - in that case, perhaps the use of the snap_daemon user via system-usernames could help so that the snap doesn’t have to run as root.
However, even in this case, the daemon will still be started as root and it would have to drop privileges to the snap-daemon user, so this doesn’t entirely alleviate the security concern.
As such, if this browser-support is absolutely required, we would need to perform publisher vetting as though this were a request for classic confinement.