Cinema films normally 24fps
Pal TV normally 25fps
NTSC normally 30fps
This is all based around people doing normal thing, But when you get to sports (or fast moving action) most are filmed at 50/60fps with the odd exception where there might be a camera just shooting at 120/240fps for slow motion.
If you film a fast moving sport at 24fps you'll be using a shutter speed of 1/48th (1/50th) so there will be a lot of motion blur and your video will never look clear and sharp. Filming at 50/60fps so using 1/100th (1/120th) each image will be sharper so your video will look sharper.
The other way to think is hold your hand out infront of you and shake it, you dont have to shake it fast to see motion blur, if your frame rate is to high you wont get that motion blur and films of things like the kids birthday party will have an unnatural look to them.
The other thing to take into account is file size and where and how the finished film is being viewed. If you shoot everything at 4k 50fps you'll soon be upgrading your hard drive, also because that file is big and requires a lot of bandwidth and processing power unless the person watching has a good conection then the video could be unwatchable or very blocky, if your computer hasnt got a lot of memory/quick processor then editing is going to take longer.
There are a lot of compromises to be made.
I normally render all my stuff at 1080 as I know that 98% of the people watching it will be on a phone, which mostly all have a 1080 screen, why render in 4k for phone users? Plus with shooting at 4k and rendering at 1080 i can zoom in a bit in post without effecting the quality.