Not sure if it matters too much from an individualistic perspective. Near light-speed travel will allow a person to go anywhere instantaneously, they'd just have to contend with leaving the time and space they know behind them.
Near-light-speed travel to the Moon would take a few seconds. Near-light-speed travel to Mars would take longer than my drive to the grocery store. These are not "instantaneously."
Not literally instantaneous, but still practically instantaneous at the scale of the solar system.
Only if you ignore the enormous acceleration/deceleration forces needed for this.
I definitely agree that such travel would require enormous amounts of energy.
[0]: https://en.wikipedia.org/wiki/Space_travel_under_constant_ac...
Time dilation doesn't matter here.