For something to be considered a bitcoin exchange traded fund it would need to capture the movement of the price of bitcoin itself in its price and be traded on a regulated exchange. A Bitcoin ETF would be similar to a commodity ETF like $GLD or $SLV. While there is currently no actual bitcoin ETF yet, there are two things that are close that can be traded in most stock brokerage accounts.
$GBTC: Grayscale Bitcoin Trust is an off-exchange traded fund launched and managed by Grayscale Investments, LLC. The fund invests in Bitcoins. It invests through derivatives such as futures, swaps, and other CFTC-regulated derivatives that reference digital currencies. The fund seeks to track the performance of the TradeBlock XBX Index. Grayscale Bitcoin Trust was formed on September 25, 2013 and is domiciled in United States.  It trades on the over-the-counter (OTC) market or pink sheets and not a major exchange. Some brokers do not allow it as it is not exchange traded and not held to listing standards.
$BITQ: The Bitwise Crypto Industry Innovators ETF invests in the companies leading the new crypto economy. BITQ tracks an index designed with Bitwise’s industry expertise to identify the pioneering companies that generate the majority of their revenue from their crypto business activities.  It’s a traditional ETF that gives the trader or investor exposure to companies whose business is heavily correlated with the bitcoin price. This ETF is how an investor could allocate capital to the bitcoin sector in their stock portfolio. This is a derivative of bitcoin exposure as it is through second hand company investment that comes with both the benefits of the companies success along with the risks of their operation and management. It trades on the NYSE Arca so it is exchange listed and must maintain high listing standards.
Top 10 $BITQ Holdings DATA AS OF 06/07/2021
RIOT BLOCKCHAIN INC RIOT 9.58%
MICROSTRATEGY INC MSTR 9.55%
COINBASE GLOBAL COIN 9.44%
CANAAN ADR REP 15 CAN 5.20%
MARATHON DIGITAL HOLDINGS INC MARA 4.81%
GALAXY DIGITAL HOLDI GLXY CN 4.70%
VOYAGER DIGITAL VYGR CN 4.59%
SILVERGATE CAPITAL CORP SI 4.52%
NORTHERN DATA NB2 GR 4.42%
BITFARMS BITF CN 4.16%
These above options are for stock traders that want exposure to bitcoin inside their stock brokerage account and portfolios. For those that want to trade cryptocurrencies and have direct exposure to bitcoin, Coinbase and RobinHood both offer direct trading and investing in bitcoin. Futures traders can also trade bitcoin futures for leverage and expanded options outside stock exchanges and cryptocurrency brokers.