Based on the discussion above, I propose to update the beggining of the wiki article about footpath as follows:
The tag highway=footway is used for mapping minor pathways which are used mainly or exclusively by pedestrians. In most countries, they tend to be constructed and either paved or with smooth surface (compacted, fine gravel, wooden or similar). Anyone including the elderly and small children and quite often also wheelchair users can use them with ease. You more often find them in urban settings, but not always.
Paths that are maintained either by people walking on them or that are only minimally constructed are usually tagged as highway=path in most countries. Their surface might be uneven and some or even high level of physical fitness and situational awareness might be needed to use them. More often but not always, they are located outside of urban enviromnent. Hiking trails are a typical example. Sac_scale=, trail_visibility=, surface=* and access=* are useful. In some countries like UK or Germany, this distinction does not hold and highway=path and highway=footway can be used interchangeably.
For wider pedestrianised streets, typically, lined with shops or commercial buildings use the tag highway=pedestrian.
If you are mapping footpaths in the UK (specifically England and Wales) see UK public rights of way.
For pathways designated for cyclists only, consider instead using the tag highway=cycleway.
etc.
I tried to stress the built/unbuilt distinction.
Note I am also changing the link for the UK access stuff - I think it got outdated as the current link is redirected. I hope I got the intended target right (it is repeated in the See also section)
BTW: From the wiki, this page is also linked: Path controversy - OpenStreetMap Wiki
To me it seems somehow outdated as it does not reflect the controversy about alpinist paths and in general is quite hard to follow for me. Not sure if it should not be rewritten from scratch, most of it is more than ten years old.