I don't think that the panel understands how the current APR for HBD savings works (or at least the conversation makes it appear so). The interest is not locked for 3.5 days...period. The interest is paid every 30 days...not 3.5 days. The waiting period for a withdrawal from the savings account is 3 days, not 3.5 and that is a totally different issue.
At 20% APR the interest paid every 30 days is 1.67% (dividing 20 by 12).