When a collectible becomes valuable, it can become money. When bitcoins became valuable, you could take advantage of their excellent system for conducting financial transactions. However, the system remains the same, regardless of how many people participate in it. Therefore, the system itself can not be responsible for those costs which people are investing in bitcoins.
It's different in bitcoin as the more people are adopting with it the value will appreciate more, and since we only have a limited supply that makes the game more entertaining to watch. I have trust bitcoin and I have invested with it, and I can say that my investment is worth for me because bitcoin is worth. It cannot be denied that we are getting the best benefits of using bitcoin and we can only get that from useful asset, and that is bitcoin.