Honestly, FFIII (Famicom Version) was probably the only game in the series where exploiting status effects was mandatory for survival. You often ran into groups of 6-8 opponents and they could all tear through your team pretty easily if you weren't nailing them with blind, paralyze, and poison to slow them down and save you some valuable healing.

Status magic is one of those things that was very useful in the early entries and then went out of style for a few games and then came back into being useful again recently. Slow, Sap, and Paralyze are invaluable in FFIV for instance but by FFV, status magic that isn't really Time Magic goes out of style for the next few days. I mean FFV-X all have certain bosses/enemies that are significantly easier if you exploit status ailments but there are also very direct methods for dealing with as well so it's not as useful as early entries. XI makes them good again, XII made them almost mandatory for the Mark Hunts and XIII made it one of the game's more useful roles. It will be interesting to see if XV will bother with it though.