He's not saying they would trade 16 and 19. Mostly likely 49 and 16 to move up to around 10. That's really not a terrible price if they think the LT they are targeting can be their starting LT for the next 10 years. And Nick isn't predicting they will do that. He's just saying that IF they think they have to get a starting LT in this draft, they will need to move up to get one and that signing Landry would give them the flexibility to use 16 and 49 to go up for a LT.
Personally, I'd rather stay put and get a guy in the 2nd or 3rd that can develop under Hurst who I think is solid. But, if the Saints think that Hurst can't do the job I could understand moving up with 16 and 49. I could not understand moving up with 16 an 19.