So, if you're standing …

My thought is: "Time dilation is actually good for interstellar travel" Say we have a space ship that travel at 50% of light speed.

Time dilation is a difference in the elapsed time measured by two clocks, either due to them having a velocity relative to each other, or by there being a gravitational potential difference between their … It is mind-boggling to comprehend that one hour can pass by on one planet while seven years pass by on Earth. - ericbsantana/interstellar-time-dilation Did you watch the movie Interstellar and come out wondering how any of it was possible? If you're curious, the equation for time dilation is actually surprisingly simple: Δt' = Δt / √( 1 - v 2 / c 2) Where t' is an observer's time "speed," t is a traveler's time "speed," and v is velocity in terms of c. The closer v gets to c the slower time moves.
This space ship will take 8.6 years (earth time) to reach Alpha Centauri. The time dilation factor is exactly 1 hour on Milller per 7 years of Earth time due to the gravitational forces of Gargantua moving the planet through empty space at roughly 99.99999998% the speed of light.

He is moving through a higher dimension rather than following time dilation in our own spacetime. It's not time dilation. Once Cooper has entered the tesseract, he can see the whole of Murph's timeline in sections as he moves around.

The explanation comes down to what scientists call Gravitational Time Dilation. The 61,000 time dilation factor on Milner's planet is not due to relative velocity time dilation, but gravitational time dilation. To travel to nearest star Alpha Centauri which is about 4.3 light years away.
Additionally, it is not due to the gravity on the planet itself, but the massive gravitational well of Gargantua (the supermassive spinning black hole). A time dilation calculator of Miller's planet from Interstellar. TARS tells him that the tesseract is a manifestation of five dimensions.