Buying a BTC ETF is not a good idea. When you buy an ETF, you don’t actually own anything , you only own an IOU, a promise that someone else owns the actual asset for you. You have to trust the other party that they really possess the Bitcoin and that they will pay you when you ask for it.
For example, what if things go wrong hyperinflation hits the US, a civil war breaks out, or there is anarchy? How will you then access your money? In such situations, there is a high chance you could lose everything.
On the other hand, when you own Bitcoin on your hardware wallet, you truly own a bearer asset. You can always carry it with you, go anywhere in the world, and exchange it for local currency. You can directly use and spend Bitcoin, which ETFs or IOUs do not allow.
But as Z-tight said, this is at least better than not buying and many times better than many people still being hostile and distrustful of bitcoin, so far.
In my opinion, if OP is new then this is not a bad start and there is nothing to criticize him about. Newbies need more time to learn about bitcoin and once they understand enough, they can convert their ETF into real bitcoin at any time. This is not a big or serious issue and we do not need to be too harsh on those who are new to bitcoin but have already believed and decided to invest in it.