FUDGE dice are ridiculously easy to replace with a regular d6 without being annoying. I think a 1-2 is a minus, 3-4 is nothing, and 5-6 is a plus. Something like that.
Yes they're fine because they don't need a table or an equivalent.
Whereas most NSD situations do require a table, often a somewhat annoying/fiddly one.
For me, what a game's choice to go NSD means, at this point, after 34 years of RPGs, is "I'm not going to bother to run it and probably not even play it". I understand that you can do some things statistically with symbol-laden NSDs/tables that you can't do with normal dice without tables, but the majority of NSDs are horrible objects physically (unlike dice, which have been lovely for decades), unreliable and often biased (Star Wars had huge problems here - to the point where people could gain a real advantage by test-rolling the low-quality dice until they found ones which rolled favourably, which was common), and as you say, become virtually impossible to replace if a game proves unpopular or goes OOP. 3D printers are no solution because they don't produce high-enough quality objects yet (maybe one day) and are limited to hobbyist members of the middle and upper classes. Hell I know a bunch of British ultra-nerds, including multiple people with VR headsets of the expensive kinds, and I don't know a single person IRL who has a 3D printer. Apps are a more real solution but are so un-fun compared to real dice.
As a bonus with MCDM's game they were proposing not just d6-style NSDs but d8, d10, d12 and I think even d20 ones (though honestly with d20 the symbols would be so small you might as well just use a table).
@Snarf Zagyg - Agree completely with the way you break down the dice methods, though I might add that whilst dice pool games clearly fit under d20 as you say, they do lack one characteristic of that which is enough to I think classify them almost as a sub-species:
That the game will have multiple different resolution mechanisms. Moreover, these is always the implicit promise that there will be variety in terms of dice rolls- and that these variations will matter.
With WoD particularly but I think also Shadowrun there's basically only one resolution mechanic, and no real variety of die rolls.
Interesting to think about how Spire (which use the "Resistance" system) fits in - it's very close do the d6 category, but actually uses d10s for task resolution and always the same mechanism - you roll 1 to 4 d10s, take the best roll on a table (the same table is always used). But it also uses d3s, d6s, d8s, and d10s for stress damage rolls (possibly also d12s but I forget). I think it occupies a sort of interesting halfway-house between d6 games like PtbA and EZd6 and d20-style games. Which is also how it plays and is designed generally - midway between the two schools of thought.
