Affirming or encouraging her when the two of you are alone is fine, but doing the same it in front of others takes it to a whole new level. Show her you are not ashamed of her, or of your love for her, in public, and you are likely to see a nice reaction from her in private.
Beyond this, doing these things in front of others can influence how they see, and treat, your bride. Years ago I worked for a couple of home builders doing contract landscape work. I would sometimes call my wife from a construction trailer – with a bunch of construction guys over listening. When I got done I would say “I love you” – not “i love you too” or “Yeah, me to” but “I love you” as loudly as I’d said everything else. Yeah, I got teased a bit, but I noticed something amazing. When there was a lot of work my bride would come out and do some work with me, and she was treated with respect by the men. Around construction sites women are generally treated one of two ways, and neither of them is respectful. Apparently my unabashed love for my wife earned her points with the men who overheard me.
Open love and respect say something to the recipient and those around you. Open disdain does the same, but in the opposite direction.