If you use the 'time remapping' settings in blender you will be changing the global speed of the whole animation but keep the timebase (framerate). Most video editing software (not blender's VSE) can deal with different timebase for elements on the timeline. The playback speed will need to increase as well to keep a second still a second. If you change the 'framerate', you will generate more frames for every second of video. What is the difference between changing framerate and time remapping? you ask. If your goal is to have more frames to be able to stretch the playback and generate 'slow motion' or speed ramps without having to interpolate frames, then render the animation at 60fps or higher and play back at 24 fps so that those 60 frames will play over two and a half seconds (roughly) If you generate 60, then you need to playback at 60fps to get that same second on the screen, or you need to play some frames and drop (ignore) others if playing back at 24fps. For example: a single second at 24fps needs 24 frames. If you want a second of video you need as many frames as the framerate (time base) you are working on.

Time is a relative concept when it comes to video and framerates.

Blender intro animation