The Tahoe plot did have a lot of moving parts, but it had the advantage (if Michael had been killed) of pointing the finger at Pentangeli. Michael's survival saved Pentangeli because Michael immediately figured out that Frankie really wasn't clever or ambitious enough to have attempted it. The Havana plot was much more straightforward, but it put Roth in play--because, if it had succeeded, it would have happened on his turf, with Michael's $2 million in his hands, and after Roth had promised big chunks of his Havana gaming empire to other operators.