”My friend wants to ride with me but they’re too scared to ride on roads. Where can we ride on cycleways from Helsinki?” is a question I’ve had to answer on local cycling groups more than once. It seems reasonable to me that a map should be able to answer a question like that.
Reading your comment made me realize there may be some ”obvious” things that may not be so obvious to people in different locations and climates.
Nearly all cycleways in Finland are wide and straight enough to be plowed with normal tractor sized equipment, same as is used for residential streets. (Plowing here includes techniques like running the plow across the ground to scrape off ice, which only works well with fairly heavy equipment.) The few cycleways that are not wide enough for this, well, their designers get an earful from users every winter.
Bumpiness is mostly about frost heaving and related processes, and situation on the ground will change quite a lot between re-paving. Based on local observation, pothole fixing crews operate mostly inside towns, and long and out of way cycleways may have to wait until full re-paving. (Very recently bumpiness is mostly about fiber optic crews doing whatever they want to roads and cycleways in cities, but nobody is tagging that to OSM.)
Unpaved cycleways are mostly in parks (either the grassy field kind or the forest inside city limits kind). These may be locally important part of cycleway infra (mainly due to low amount of intersections with cars), even though their maintenance is sometimes handled by the outdoors recreation department rather than road maintenance. Some exceptions exist, e.g. the small town of Kinnula has a very atypical amount of cycleways for its size and many of those are unpaved. (Surface tagging is very incomplete.)