What are the main differences between the Flare Gun and the Detonator?

http://wiki.teamfortress.com/wiki/Pyro_weapons#Secondary

Flare Gun:

• Guarantees Critical damage on burning targets.
• On hit: ignites enemy.

Detonator

• Guarantees Mini-Crit damage on burning targets (only when flare is not detonated).
• On hit: ignites enemy.
• alt-fire: detonates flare in flight, creating a small explosion which ignites nearby players, but does less damage than a normal hit. The knockback can be used to flare jump.
• Flares detonate on impact, with a greatly reduced explosion radius.
• On detonation flare destroys enemy sticky bombs.
• 25% explosion self-damage vulnerability on user.

From the Team Fortress Wiki:

The weapon's main trait, however, is its eponymous detonation ability. While a flare is in flight, pressing alt-fire will cause it to explode, creating a small blast radius which damages and ignites nearby enemy players, additionally destroying sticky bombs. Flares will also explode upon contact with the world, but this explosion will not damage or knock back enemies.

This explosion provides a couple of neat things:

• You can detonate the flare in mid-air, meaning you could use it to ignite enemies who are hiding behind cover. It also means you can recover from near-miss shots to a degree.
• You can ignite multiple enemies at once, making for a fairly effective ranged attack.