Funding your strike fiat balance with ACH payment methods are slow..very slow.
Strike is protecting themselves from non-sufficient fund rejections 1-5 days after you initiate a fiat deposit.
I bet they were taking some losses from their very generous policy. Imagine this:
- user deposits $100 fiat over ACH to strike
- user immediately pays themselves $100 in btc over LN
- days later, users bank rejects the withdrawal
- strike lost $100 because they can’t claw back the btc

