Camshafts, idle quality, driveability and LSA-REAL WORLD EXP and OPINION
If you can pick cam from its opening and closing points and use that to guide your lsa and duration picks I would imagine that's probably the ultimate way if you have the knowledge and experience. I would have no clue that way.
For the average guy most can pick duration and lift for the basic application and since most cams are ground on a few lsa it's a pretty simple affair. That's as far as I go into help picking when asked. For myself Id pick a range for lift and overlap and plug many different cams as can that fall into those criteria into my dyno software and use it to narrow my decision.