You're trying to have an opinion on the competitive aspect of TFT without actually trying it for yourself.
Every game, whether it's video games or other games like soccer or basketball, can seem less skill expressive when played at a normal " for fun " level, or not played at all. Take them to a competitive scene and you'll notice all the skills required to actually win against others and be among the best.
The same thing applies to regular League and TFT. You won't notice how the game actually requires skill until you participate in the war that is ranked. Once you get beaten by the ones better than you, even if the RNG was against them, because they are more skilled and made better decisions than you, then you will realize how skill actually matters in these games, as well!
Also, the game is not only luck and positioning. One of the hardest part of the game is knowing when to transition between comps and know when to give up on going a certain comp. The game, although screwed up by the current RNG system, still has a big skill element of decision making to it.
This becomes even more important when you have bad luck with items. Knowing how to bypass the bad RNG and make the right decisions based on what is or is not being played by other players, what units/items are available to me from the shop/PvE rounds, what state are the units in (2+ stars or not), what enemy comps have blitz, etc.
If you bypass the RNG aspect of the game, there is so much more to do and to learn from playing it competitively. As someone in D4, I can tell the difference between someone who plays the game only in normals, someone in silver, and someone in D4+. The quality of the games are so much different and the skill expression is very apparent in higher elos.