That's never a good argument. -Using something not said as evidence for or against something actually said.
It doesn't say 'not visible' so then it must be visible???
Why do you have a "mark of the beast" and you use the same word you would use for brand on a horse. It is so people can see that this horse belongs to you. That doesn't mean that it must be visible to the naked eye, but that is the purpose. Store owners, and police, and any gate keeper is going to want to see that you have the mark. This isn't just so you can buy, it is also so you can sell.
True, an RFID would be picked up by other sensors so you could always detect it. But you don't know if it is on the hand or the forehead, it is nice to make it easily identifiable to people by eye.
The flip side of course is people will tatoo fake marks, but that would be easy to spot since there is no RFID signal.
The concept of taking a mark is the same idea expressed by having a seal upon the forehead or hand to indicate those who have pledged themselves and to whom. In scripture elsewhere (like Rev 9) we see the angel being told to 'damage only those- who did not have the seal of God on their forehead.
That doesn't necessitate that it must be a visible mark of God. And yes, two different Greek words are used, but both are used to describe 'marking' something to designate authority or ownership.
Yes, it is quite obvious that God, and Satan do not need this to be visible to the eye for them to see it. But what about Satan's minions? What about the old "turn in your neighbor" approach to totalitarianism?
was a seal stamped with the name and date of the emperor and attached to commercial documents. The same word could be used to describe the branding of an animal with the symbol of one who it belongs to. Taken farther, it's akin to piercing the ear of a slave with an awl. And yes, these are all physical (visible) things. But we are marked (sealed) in the spirit with an invisible stamp that denotes who our Lord is. The angels have no need of physical markings to determine who one belongs to.
Conceptually, the idea of a mark is just that---- whatever the mark will be, it will be true to the principle of being subject to someone or something referred to in scripture as the beast.
Your only argument that it isn't visible is that it doesn't have to be for angels and God. But the mark will be enforced by people, they could be your neighbor, a person on the street, a cop, a cashier, etc.
You are talking about billions of people. When the first million get the mark they will go to their friends and family and say "see what I got". Therefore it makes sense that these people who are not yet marked can see it.
The bottom line is there is no reason at all in the Bible to say definitively that you can't see it, and since John is describing it by comparing it to things that we can see it seems strange he would not mention that it cannot be seen if it cannot be seen.
Finally, "pattern is prophecy". The number tatooe'd to prisoners in the Holocaust is a prefigure of the mark of the beast.