Please note that the wiki page for tactile_paving=* already mentions since 13 years with only minor changes to the wording since that this tag can be added to highway=steps to denote tactile paving on these…
[…] even if there is only a spot with tactile paving at each end. The stairs themselves are sufficient tactile objects to detect with a white cane.
There is no mention of that tactile_paving=* could (instead/also) be tagged on the start/end nodes of that way. (And I do think that this would be problematic, see note 1.)
So, the real question is not whether to tag it at all on ways but whether tactile paving at the top of the stairs only would be sufficient to tag it with yes or not. The reasoning being that only at the top of the stairs, there is danger of falling.
Note 1:
tactile_paving=* on start and end nodes of steps would be problematic. This tag would then not be added to any feature, i.e. it is likely the only tag on that node. This would be difficult to process both for data consumers and difficult to represent with editor presets (like iD, JOSM): Without a feature it is attached to, tactile_paving=* does not really have any meaning. In all current cases, tactile_paving=* is always attached to a feature.
To be consistent with the other uses, it would be necessary to invent a feature like highway=start_of_steps tagged on such nodes. But this would be kind of ridiculous.
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