Using native image sizes on the web vs responsive sizes

Is there any benefit to using the exact native image size on the web verses an image the scales with the viewports's size?

For example, if I have a 1000x1000px 2x image, should I only display it at 500x500px and then use a media query / a different smaller image for smaller screens? Or would the 1000x1000px image scaling to smaller viewports be find?

I'm trying to understand the tradeoffs of having a larger image scale with the container since it is less production work and in theory should look good at lower resolutions.