Hasty? I think not lol since they're cheap, and will rise in price :)
Did you think of dual wield and the str you get with battle swords? For when you're not smash/WM spamming, or are doing N+smash/windmill.
54 (4/5 upgrades) battle sword + 56 max (from artisan, 140 str from two swords) = 110 max. Adding G14 special upgrades (+6) you get another 31 max.
110 + 31 = 141 max.
vs
What'd you say? 92?
Also yeah, if they get special upgrades they'll be 92+31=123 max. Still 141 > 123.
However yes, I will say that in terms of smash/mill the damage is very close. Battle swords still win (for now?) but I already said that, and admitted it was close, in an earlier post
Battle Swords = 82 Max each, 110 Max dual-N
War Swords = 92 Max each, 104 Max dual-N
You applied double-Str only for Battle Swords. Again, the gap isn't very significant and you're still relying on a 0-70 Str variable. The fact that Battle Swords are cheap will be outweighed by the cost of Artisan Resets and Re-upgrades, unless you get really lucky from the start.
Battle Swords with S6 = 113 Max each, 141 Max dual-N
War Swords with S6 = 123 Max each, 135 Max dual-N
Even with N and double-counting Str, War Swords are still much more feasible and pretty comparable. Honestly I wouldn't even think of going for a Battle Sword unless you have a plethora of NX, and even then I'd rather shell out for some better enchants instead.