Is there any benefit to, as far as is humanly possible, total dedication to the precepts, in zen? Is there any benefit to, as far as is humanly possible, total dedication to the precepts, in zen?

So total celibacy, vegetarianism and non violence to any life form, complete abstinence form alcohol, etc..

For the laity without a zen master.
"Perfect" virtue (when based on right view, which could be problematic with certain "Zen-views") is the condition for no remorse, no remorse... happiness, concentration, ... insight... liberation.

When focusing on the foundations, one works smart and straight forward till perfection. One hearing then the good teachings it might plopp.

Good associations/relations so that it might work.

(Note: not given to keep or give to keep in the wheel of trade, exchange, stacks... binding to worlds but for using as escape)