<p>Quite apart from community norms and the optics of begging for reputation, accepting an answer also visually marks the question as “answered” (which means “no need to spend more time on it/check it” if you are looking for something to do and also “likely to provide a solution” if you are searching past questions to solve a problem you are having).</p>

<p>A lot of the discussion seems to focus on quality and reputation but in my mind the answer doesn't even have to be great or especially deserving to be accepted. If it provides a solution or somehow addresses the question (which might itself not be particularly deep or interesting), then the question ought to be marked as “answered” or the OP should explain what's missing.</p>

<p>Unlike upvotes, it's not so much about the reputation than it is about site management and good record keeping. I often ask people to consider accepting an answer (my own or someone else's) or to “upgrade” short comments to a full answer for this reason (it's not uncommon for a brief comment that seems unremarkable to its author to fully and completely address a question).</p>
