Don't know about it being just for show...
I was told by a gurmukh that when you're meditating (or in my case, trying to meditate) then it's extremely easy for the mind to wander. Therefore, using some sort of basis for your senses helps the mind to settle down.
TOUCH: When you use a mala to do simran, your mind focuses (through your nerves) on the mala.
SMELL: Some Gursikhs use incense to stop the nose from wandering (esp if you have the smell of hot pizza right outside your room)
SIGHT: Most Gursikhs close their eyes but you can focus our eyes on a stationary object, and I've found that it helps (and it helps from falling asleep!)
SOUND: If you repeat the mantr aloud then your ears will adjust to that one sound and not be distracted as easily.
And once again about the tuks, people have different interpretations.
For example, the second one, I would take that as Bhagat Kabeer trying to highlight his pyaas for Akaal, and in that statement, he's saying, "I want Darshan of Akall so badly that I can't even sit still and do my bhagti." I don't take it to mean that he's actually denouncing the mala, just that he's so in love with Akaal that it's all he can think about.
Yeah but this raises the question is simran only reciting vaheguru, or is it thinking about vaheguru aswell as reciting? - is it simran when its from your mouth alone? or is it when you are doing vaheguru from within constantly. In that case - if Bhagat Kabeer Jee is sooo in love with maharaj, surely then the simran is happening internally?