I sense we're veering off topic here.
Yes, I suppose you could construe NEEDFUL to be BENEFICIAL if the words were nuanced in a specific context; though it appears that beneficial is somewhat dependent on needful in the case provided. But if both are placed side by side -- "am I doing this because it is inescapable if I'm going to fulfil the Lord's command, or am I doing this because it adds something to the worship itself," the two are clearly distinguishable.
Yes, I suppose you could construe NEEDFUL to be BENEFICIAL if the words were nuanced in a specific context; though it appears that beneficial is somewhat dependent on needful in the case provided. But if both are placed side by side -- "am I doing this because it is inescapable if I'm going to fulfil the Lord's command, or am I doing this because it adds something to the worship itself," the two are clearly distinguishable.