Shooting at 60fps, export in 24fps I would like to be able to add slow motion where ever I need in post so I would like to shoot only in 60fps. 
The export target is youtube and since I would like to keep a sort of cinematic look, the export frame rate I would like to keep in 24fps. 

I previously did some tests in Premiere Pro, and it alloved me to add and edit clips with various frame rates and export them in the lowest of them - 24fps.

The video looks good, hovewer from informations I'm reading, it's not good to do that for my future workflows...
Can you please explain me why ? 

If it's bad, will it helps if I will for future shoot in 60fps and export in 30fps ? 

Thank you
I always shoot videos with slowest 50fps in my camera, Full HD. like you said, it provided slow motion &amp; this setting has clearer movement. Sometimes I change back to 25fps when I meet some conditions.

Export in 24fps can be used for website, for example published for vevo, youtube channels etc. Because fast buffering and light file size. It also for animation &amp; Music Video (MV). Full HD.

Export in 30fps is for NTSC Television Boardcasting &amp; it smooth for NTSC live, like TV shows in America &amp; Japan. If you published a video in 30fps alike TV shows.
Other countries used slow motion, able to published in 25fps for PAL TV. FHD, QHD. Mosty they're 4k now, their videos are very sharp.

Cinematic will be more optional and more setting &amp; editing, mostly people used as many as fps their camera have, until 4k/8k 120fps+lighting achieved proffessional result. Export in 25fps, 60fps, etc. It is optional.

You want to be videographer,editor for Music Video, web, etc? Export in 24fps. (Actually your camera fps setting &amp; export is good enough, just remember the quality of camera shoot, quality of resolution FHD or above)

Or Videographer,editor for live or non-live boardcasting TV shows? Export in 30fps. (The researched answer is for Television Boardcasting, 30fps)