The @minnowbooster and a few other bots allow you to delegate SP and in return you get some of the earnings. But the big upvote bots exclude you from that and I think they generate the most of the business for upvotes. In terms of exposure you're right depending on the circumstances, but I think it's better to comment on articles with content you write about yourself and grow a follower base that has an interest in your content.
I wrote an extensive article about the upvote bot issue. Maybe you find it interesting.