Nobody just sits on the edge of their chair waiting to be biffed that a bounce message is waiting for them. I for one have my mailer set up to collect those in a
virtual folder so I can deal all such at once. Digestification by default won't hurt I believe.
OTOH, there are reports that when mailing list is moved or a large number of new addresses are added, thousands of bounce notices may be generated. In such cases digestification is almost necessary.