Question regarding cross training.

I was wondering what the advantages and disadvantages of mixing muay thai leg work with a center-line CMA or western boxing like upper body method would be.

The Muay Thai guys always seem to have the wide(non center-line) arm positions. I’m wondering how things would differ without it. I assume that clinching would be more difficult.

Thanks for any comments. I asked this last week in the other arts section, but I didn’t get any replies so I’m trying here now. Thanks again.