Rick is dead right on this.
For me it also explains why right-handed people pluck the strings with their dominant hand.
The first stringed instruments were fixed length strings: Lyres, harps, zithers…
Of course everyone plucked the strings with their dominant hand, holding the instrument with their other one or later adding accompaniment.
Eventually, they noticed that by shortening the strings, pressing down with their ‘free’ hand they could vary the pitch. It was a natural progression. From the very beginning, tradition taught that you pluck with your dominant hand and fret with the ‘free’ hand.
Guitar playing, however, has two different complicated tasks for each hand. Whichever way you learn you’re going to struggle with an aspect that you would find easier with your dominant hand.
For me the hardest part of learning guitar was trying to get my left hand to accurately fret the chords. (Don’t get me started on the idea of speedy solo fretwork 
)
I don’t buy the idea that rhythm is better on one side. (Justin teaches we should keep the rhythm by tapping our left foot). Like everything else it’s all down to practice and personal preference.
I’ve never heard a piano player complain they can’t keep the rhythm with their left hand, (although I’m sure that problem exists). My son is a lefty and learned righty guitar without a second thought.
Choose whatever you fancy, for whatever reason.
Then practice! 
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