ETNs sounds like covered warrants issued by banks.No, the point is that these are not ETF's. Probably more accurate to call them ETN's, though that term has fallen out of use.
If you own the QQQ's ETF for ex you have the right to transfer that product into some notional value of actual Nasdaq 100 stocks. ETFs have intrinsic value of the product they track.
These ETN products dont have intrinsic value outside of the integrity and/or credit of the underwriting institution. The portfolio underwriting the ETN risk can literally be nonexistent.