You could directly observe history and remove any ambiguity about the events of the past.
You could recover and/or hide lost treasures for future recovery
You could observe a possible future to see how decisions and events played out.
Disadvantages
You probably couldn't survive it. The behavior of the matter and energy that make up "you" follow physical laws predicated on the linear flow of information. If you could step outside of the flow of time, you'd probably also be stepping outside of the laws that keep your very atoms together.
Any past or future observed by a time traveler would inevitably become disconnected from that of the traveler. Either the traveler themselves would become an anomaly as their influence moved upstream or any influences would result in branches.
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Advantages
You could directly observe history and remove any ambiguity about the events of the past.
You could recover and/or hide lost treasures for future recovery
You could observe a possible future to see how decisions and events played out.
Disadvantages
You probably couldn't survive it. The behavior of the matter and energy that make up "you" follow physical laws predicated on the linear flow of information. If you could step outside of the flow of time, you'd probably also be stepping outside of the laws that keep your very atoms together.
Any past or future observed by a time traveler would inevitably become disconnected from that of the traveler. Either the traveler themselves would become an anomaly as their influence moved upstream or any influences would result in branches.