It’s both
Another example being kaku again. Even without his physical swords he’s still a swordsman because he considers his legs to be blades. All of cp9 can use tempest kick tho
King was stronger than start of wano Zoro
Both used swords but only Zoro’s a swordsman
At the same time sword duels exist. We even saw them have a temporary one before king went all out again. Zoro is still the better more skilled swordsman despite being weaker
In the shanks case if he isn’t considered a swordsman that doesn’t mean his swordsmanship is bad. Put him against Tashigi in a sword duel he’d still win but depending on what’s considered sword skills you might be able to argue Tashigi being more skilled like zoro vs king
Another example being kaku again. Even without his physical swords he’s still a swordsman because he considers his legs to be blades. All of cp9 can use tempest kick tho
King was stronger than start of wano Zoro
Both used swords but only Zoro’s a swordsman
At the same time sword duels exist. We even saw them have a temporary one before king went all out again. Zoro is still the better more skilled swordsman despite being weaker

In the shanks case if he isn’t considered a swordsman that doesn’t mean his swordsmanship is bad. Put him against Tashigi in a sword duel he’d still win but depending on what’s considered sword skills you might be able to argue Tashigi being more skilled like zoro vs king