This is very good news.

• Combat rehypothecation (the big thing)
• Force exchange fees down across the board (IBIT is 0.25% away from spot)
• Allow people who have 401K or IRA to purchase ETF and later take full custody
• Allow people who have coins, to transfer to a 401K / IRA for tax / estate planning reasons
• Prevent needless sales (and thus needless taxes) when moving from one species to another