Setting beneficiaries does not affect curation in any way. (Declining rewards does also disable curation rewards.)
I usually decline or burn my own author rewards because I feel I'm already well enough compensated for being here as a stakeholder and witness. I don't need any more.
I'm strongly in favor of burning at this time because I see relatively little rewards being directed toward strongly beneficial contributions to Steem (though when I do see those, and when I see good community engagement, I upvote those too). I think Steem clearly benefits from reduced inflation and reduced current and future selling pressure at this time (which burning accompishes), but of course that is my subjective opinion.
RE: 2019 Steemfest ticket contest - winners announced