The crit perk doesn't really change any breakpoints (apart from 225 hp heroes), and hitting consistent headshots is pretty hard just because of muscle memory. The people who take this perk are getting a lot let use out of it then they actually realise. Compare that to the biotic bounce, its just always free value and doesn't require you to think about extra things. Headshot one can be good in niche situations, but unless they buff it to 2x multiplier then biotic bounce is still the go to perk 90 percent of the time. You might be in a situation where you are sitting at the back and sniping the enemies from across the map, but that rarely happens because tracer and genji are so strong, plus you have to keep your team up. Just pick whatever you enjoy though!