What it is for
A weather warning. A change of bin day. "I am away for a fortnight, this is the number to ring." The kind of message that is worth sending to everyone and never gets sent because doing it one tenant at a time is forty minutes.
The preview is compulsory
The send button does not exist until the recipients have been fetched and shown to you. That is deliberate. The mistake people actually make is not a typo in the message, it is not realising who was on the list, and that one cannot be undone.
Who receives it
Current tenants, with the property each one is at shown next to their name, so you can see at a glance whether the list matches what you expected.
Bulk work more generally
Selecting several properties and acting on all of them, sending reminders, exporting a combined pack, is available from the larger plans and to every agency workspace. On a one-property account it would be a checkbox column that never does anything.