The benefits of equipping a monster to another monster varies, depending on the card. In the case of Union monsters, they usually have the ability to save your monster from destruction by sending themselves to the graveyard, and some have added bonuses, like "Heavy Mech Support Platform" adds 500 attack to your monster. "Dragunity" is an archetype built around equipping low level Dragon-type monsters to Winged Beast-type monsters, with various effects, but no protection effect. Other cards like "Allure Queen" and "Destiny Hero - Plasma" allow you to equip your opponent's monster(s) to them, thus removing potential threats from their field. Plasma also has the added benefit of gaining attack points equal to half the equipped monster's, and negating all of your opponent's monster effects.
I run a very good dragon deck and the only equip card I run is Axe of Despair. 1000 attack.
Same as when you use a regular Equip Spell card on the opponent's monster, the monster acting as an Equip Spell Card goes to your own S/T zone.
No, the Equip card stays on your side of the field, and is under your control.
No, face-down monsters cannot be equipped.
The Equip happens on resolution of an Ignition Effect. Book of Moon can be chained to that. The target monster will flip face-down and then the Equip effect will resolve without effect because it can't equip to a Set monster. Inzektor Hornet will not move from whatever zone it started in.
Equip cards can never be attached to Set monsters. They can only ever attach to a face-up monster.
monster reborn
Yes, Flint would be destroyed in that case. You equip Flint to a monster, and if that monster would be destroyed, then you (must) re-equip it to another monster. Though initially you'd probably place it one the opponent's monster, the mandatory re-equip may mean you have to put it on one of your own. However if the equipped monster is not 'destroyed', ie, if it is tributed, or removed from play by an effect such as Caius the Shadow Monarch, then Flint itself will be destroyed and go to the graveyard.
magic trap and monster
Yes, it does have to be in your hand.
other yugioh cards monster the higher attack points the better
Yes, monsters acting as Equip cards are treated as Equip Spell Cards and are treated as such for the purposes of Spell destruction card.
No you choose a new target and plz read the rule book.
10 equip cards can be equipped to 1 monster :)
Yes you can. Since its effect says "If...you can", it will not miss timing. The Synchro monster would be out on the field when Vylon Prism hits the Graveyard, so you can equip it.
the card of armor breaker is an equip so at the moment you put it as equip there is no tipe of monster it transforms into a spell card so amor breaker is destroied
No, Mystical Knight of Jackal is a Beast-Warrior. It does not count as Warrior-type.