In most cases going to overtime is a 50-50 W/L proposition while a 2 pt conversion is also about a 50-50 succeed/fail proposition, so it's certainly s decision that can go either way.
If you think you have a better than 50% chance of converting, you go for it. If your offense is way better than your defense, you might also want to go for it.
I think the announcers last night said that the LAC were 5-7 on the year on 2-pt conversions, so they probably were thinking it was better than a 50-50 shot, especially with how they were playing.
I wouldn't always go that way, but based on the circumstances I think it is justifiable.