For the HTML title attribute, Mozilla's docs mention...
Use of the title attribute is highly problematic for:
People using touch-only devices People navigating with keyboards People navigating with assistive technology such as screen readers or magnifiers People experiencing fine motor control impairment People with cognitive concerns
This gives me a seed of doubt whether I can innocuously use title all over the place.
Would the mere existence of title actually introduce problems for certain users?
Or put another way, is there any benefit using title other than for showing-supplementary-information-as-rudimentary-tooltips-for-mouse-users-that-hover-an-element?
I'm just trying to maximize my UX & accessibility optimizations to 110%.
I can conceive of three different problems that using title attributes can introduce for those various groups.
Some users don't use technology that would display the title attribute. This isn't a problem is the title attribute contains information that isn't required to understand the content.
A tooltip might cover up some other information when it is rendered. You can probably compensate for this with space. Don't cram everything together. Allow enough room on a hover target so a tooltip can render in empty space, or at least space that doesn't contain information about the element being hovered.
If you scatter titles in the middle of a sentence, then I expect some screen readers will interrupt the sentence to read the tooltip. This won't make it easy to understand the document if it happens a lot.
I wouldn't go overboard with them.
(Related, but less of an accessibility issue, if the titles duplicate information in the text, then it is going to be very repetitive and annoying).