If they are handling billions in trades per day that means trade volume is up high.
A small personal wallet may not matter, but the combined value of all wallets not involved in those trades does matter.
Effectively, by holding I am saying "the ratio of trade volume to available currency is going to improve the value of the currency over time"
I am not saying "I will be able to find some idiot to buy my crypto for more than I paid for it as part of a ponzi scheme"
tho I do not think it will always translate to higher market price and valuation in future since the price is determined by a range of factors that are impossible to predict like bugs, stagnation, quantum crypto cracking or just global market fluctuations. this is where I say it need not be seen as a pure investment. market price of ETH might be the same in 1 or 10 years as it is today and network will still have created utility and value all that time for those that did not view the base token as a pure investment.