Well, Bushido still needs parry to use evasion.

The formula multiplies your bushido skill by your parry skill, so if parry is zero, your block chance is zero (though in your case will be 5% since there's a 5% bonus for either parry or bushido being 100 or more).

Without parry you only will have access to confidence (healing through poison or mortal strike until you take damage) or lightning strike (more chance to hit plus chance of direct damage) and the ability to ride lesser hiryu that you said you wanted.

Technically 90 bushido would get you those benefits. I think 50 bushido would also let you use the nerve strike with the bokuto which i suspect you are also wanting to do.