This is an old question that got bumped because of an edit, and a lot has changed.
The title tag is used ("displayed") when hovering over the element in this case a link. It can be used for tool tip info et la. It has not been a part of best practice for SEO for a while, however, tool tip information can be useful.
ARIA guidelines for usability with screen readers, would be to use the "aria-description" ...
<li><a aria-description="Widgets listed by household function" href="/widgets/by-function.html">by Function</a></li>
... for when the reading the text, which is presented to those who can visually see the page, is inadequate for those who can not. The text "by function" would normally be read and outside of content.
A better alternative would be to have the ul tag have the aria-description= "widgets list by" ... then each list item can just present the text giving context.
Input fields use title as fallback.
For input fields ARIA does not appear to be using placeholder="info" rather. In this case one can use the title attribute as a "fallback," but the "aria-labelledby='input-description'" is preferred. The ARIA-compliant reader will read the "id='input-description'" as the description for the input.
<p>Please fill in your <span id="code-label">one-time code</span> to log in.</p>
aria-label="This is ignored"
title="Get your code from the app.">
will read as "Please fill in your one-time code to log in. Input Field One-time code."
https://www.w3.org/WAI/ARIA/apg/ --ARIA Authoring Practices Guide (APG)