Don't know how time consuming it is to perform the soul ritual while you could already be farming.
But now, terrorizing whole acts, I can see a possibility of this being slightly beneficial, yes.
if you perform it well it's about 5mins, counting ritual.
some builds will have less trouble than others setting it up.
I'll go do one right now and time it and let you know. Typically I just go straight to City of the Damned and find a pack of souls in under 45 seconds or so then clear out the extra crap. You don't have to actually stay for the entire ritual, just until they start making the devil icon, then you can leave.
But I'll account for the time I go to stash and put on tgods + wisp as well and let you guys know, but I assume it'll take 3-4 minutes, maybe a little more than 2-3mins if you get lucky.
And yeah it is useful if you're terrorizing entire acts.