UPDATE 2-Bitcoin falls from peak, doubts linger over U.S. ETF boost

* Hit record $67,016 on Wednesday

* U.S. futures ETF seen as path to new investment flows

* Yet J.P. Morgan analysts see impact as limited (Adds NEW YORK dateline; includes new bitcoin-linked ETFs set to launch, updates prices)

By John McCrank and Tom Wilson

NEW YORK/LONDON, Oct 21 (Reuters) - Bitcoin on Thursday pulled back from its all-time high struck a day earlier after the debut of the first U.S. bitcoin futures exchange-traded fund, though with more such ETFs set to launch, analysts questioned the impact on cryptocurrency investment flows.

The world's largest cryptocurrency was down 3.02% at $64,000, at 10:45 a.m. Eastern time, after hitting a record $67,016 on Wednesday.

Bitcoin's rally - six-months after its previous top of $64,895 - was fueled by the launch of the ProShares Bitcoin Strategy ETF.

More futures-based bitcoin ETFs are close to launching, with The Valkyrie Bitcoin Strategy ETF set to begin trading on Friday on the Nasdaq under the ticker BTF, Nasdaq and Valkyrie confirmed. The VanEck Bitcoin Strategy ETF was expected to begin trading next week on Cboe under the ticker XBTF, Cboe said.

Investors have bet the long-awaited launch of bitcoin ETFs will lead to greater investment from both retail and institutional investors.

Yet some analysts at major banks voiced doubt over how long-lasting the boost to bitcoin's price from the ProShares ETF, which trades under the ticker BITO, would be.

"Will the launch of BITO by itself bring significantly more fresh capital into bitcoin? We doubt it given the multitude of investment choices bitcoin investors already have," J.P. Morgan analysts wrote in a note.

"The bulls are seeing this ETF as a new investment vehicle that would open the avenue for fresh capital to enter bitcoin markets. The bears are seeing the new ETF as only incremental addition to an already crowded space of bitcoin investment vehicles."

Some market players see inflation risks, rather than new investment products, as driving bitcoin's recent rally.

Still, others predicted that bitcoin's latest peak would lead to further gains this year.

"We think it's going to go higher and we can get to $80 or $90,000 by the end of this year easy, but that won't be without volatility," said Matt Dibb, COO of Singapore-based Stack Funds.

In the past few days, he said, traders were starting to pay high rates to borrow to buy bitcoin futures, "and that's a sign that we could be a bit overextended, and there could be a pullback to come."

Ether, the world's second largest cryptocurrency, rose 1% to $4,203 - close to its all-time high of $4,380, hit in May.

(Reporting by John McCrank in New York and Tom Wilson in London; additional reporting by Alun John in Hong Kong; Editing by Edwina Gibbs, William Maclean and Alison Williams)