Nah.
Not worth it, if I can get proper film matrices in under 1 hour made for peanuts (look up for DTP studio nearby) and etch it myself in another 15 minutes (if not desperate for having solder masks, otherwise another 30 minutes for doing that).
Not a single problem with 10/10 mil double sided PCBs this way (and even finer resolution at the cost of using alkaline etch bath - but I don't want something outgassing ammonia in my shop).
The biggest hassle is drilling.
I doubt there are any time savings using this conductive-ink method in any board more complex than few components - mostly due to epoxy dispensing, not even to mention robustness of prototype.
Also - what about traces resistance ?
Edit: wrong conversion of units in trace/space specs.