I’ve never actually taken a formal IQ test, and I’d have trouble justifying the time and effort.
I know exactly one person who took a formal IQ test, and it was because their parents pushed them into it in middle school.
If I won $50M in the powerball and never had to work again, maaaybe I could justify doing one just for shits and giggles.
An online IQ test is probably just as meaningful as a sorting hat quiz, or whatever the 2020s equivalent is.
Which is to say, it’s useful as a bullshitting session conversation starter with friends so long as all are aware any results should be taken with a massive grain of salt.