I play uke all the time. LOVE IT! Even done a few sessions on uke. It is tuned similar to guitar like DK said – GCEA – which would be like a capo on the 5th fret of a guitar – except the G is tuned an octave higher. So the 4th string (G) is a step away from the 1st string (A) – which is a bit weird. But all basic chord shapes stay the same. It’s fun to shred on a uke, and conversely – it’s fun to play uke voicings on a guitar. I’m not sure if I would go as far as to say that it will directly help your guitar playing, but it will expand your musical knowledge and your ear – which will help your overall musicianship and indirectly inform your guitar playing.
I will just add this – ANYTIME you are playing ANY instrument, you are becoming a better and more well-rounded musician. I can’t think of a downside to that.