The ProShares Bitcoin Strategy ETF (BITO) is a Bitcoin ETF that tracks the price of Bitcoin using Bitcoin Futures. This means that when futures are trading higher than the market price of Bitcoin, the fund may trade at a premium, and when they are trading lower, it may trade at a discount.
The ETF also charges fees which may cause the ETF to trade at a general discount to the current futures price or may cause erosion of the price over time.
The above could make BITO a better short-term trade than long-term investment, however, it is still unclear how it will trade over time since at the time of writing this the ETF has only just launched.
One important thing to note here however is that GBTC, a current instrument offered no the stock market that holds Bitcoin, initially traded at a premium but today trades at a discount, likely due to its high fees. So in short, expecting BITO to trade exactly at the market price of BTC is unlikely.
To see what the value of BITO should be, you can always check out the Proshares BITO holdings page and compare the price, to market cap, to spot price of Bitcoin.
In general, one would likely avoid long-term investments when the fund had a premium, but would not necessarily avoid short-term trades (as a premium is a bullish indicator in the short term, and also a signal that Bitcoin may be getting overextended). Meanwhile, brave traders may seek to short high premiums using puts, although your average buyer is likely going to just look at this as an easy way to buy Bitcoin on the stock market. And at its core, that is in many ways what it is despite the fact it is a futures and not spot-based ETF.