Should UX/UI designers code? Yes/no. Who cares. It's up to you.
But, the one thing every UX/UI designer should be able to do: clearly articulate the reasoning behind your design decisions.
I've worked with many designers who subconsciously understand aesthetics, layout, grids, typography, etc. But when it comes to presenting a rationale regarding their design decisions to a client or peers, they're simply not able to. It works "just cause" is not enough.
Topics to guide your design conversations:
Business Goals - how does your design align and achieve goals of the business? Every designer should have an understanding of the "why" behind their designs with metrics, stats, or examples to back it up. CEOs don't pay designers to create pretty designs, they're paying for the value those designs deliver.
Needs of Users - UX is the intersection of business goals and users needs. Be able to empathize with users, know who they are, and explain why your designs meet users needs.
Hierarchy - One of the most important aspect of design. You guide users by making prominent what's most important and obscuring what's less.
Keep in mind that the people you're presenting to are likely not designers themselves (especially clients), so what may be obvious to you may not be to them.
Your ability to communicate your design decisions increases your value as a designer by 10x. Pay as much or more attention to your communication as you do your creative skills and you'll flourish.