The section "A Clear Path to the Target", on page 205 of the PHB states "To target something, you must have a clear path to it, so it can’t be behind total cover."
The description of the Scrying spell contains the following text:
You can see and hear a particular creature you choose that is on the same plane of existence as you. The target must make a Wisdom saving throw, which is modified by how well you know the target and the sort of physical connection you have to it. If a target knows you're casting this spell, it can fail the saving throw voluntarily if it wants to be observed.
Additionally, it says:
Instead of targeting a creature, you can choose a location you have seen before as the target of this spell. When you do, the sensor appears at that location and doesn't move.
(Emphasis mine, again)
By RAW, does this mean that you can't target a creature or location that you can't already see or that is behind total cover from you? This seems to make the spell entirely useless, along with most spells that are commonly used for spying or long-range communication.
Personally, as a DM I am tempted to just throw out this entire section; it doesn't really add anything and I doubt it's worth the headache or ruining large parts of the game. However, I would like to figure out the RAW just so I know what I'm overriding, if at all. Am I missing something or is Scrying basically useless?