I rather doubt that anything about stainless steel versus titanium renders the practice of substituting the latter for the former impractical in any sense which affects aviation safety very much.
but it wasn't just the material. Had he attached the titanium strip in a manner even closely resembling the approved repair, even the titanium may have just remained in place. At least for a little longer and this would never have happened.
The point is not hanging someone for one genuine mistake but here we have a catalogue of conscious decisions that even with the best will in the world cannot be easily ignored or attributed to mttb.