The sacrifice of privileges in exchange for setting bounties has been covered in a few other questions (1, 2, etc.). While I disagree with the reasoning (my thinking is in line with that of hexafraction: privileges are to me tokens of trust, which shouldn't be undermined by the form of participation that is bounty award -- rather we're simply accepting that we'll have to work harder to get more privileges), I am willing to accept that as the rules.

However, it strikes me as odd that I am not allowed to participate in any way with the user to whom I awarded a bounty (asking for a follow-up clarification at a later date, for example).

Under-privileged users such as myself (on this SE, at least) can comment on our own questions and answers -- is there any compelling reason to restrict my right to participate in another user's answer to which I've awarded a bounty?

To me, adding the bounty was a form of "adoption" -- I gave the bounty to an existing question which had gone unanswered, as opposed to creating a duplicate question -- but now it seems I've been penalized for having done so.