Not like you're missing out on much, if you decide to completely skip Binah.
The only summon that seems to be worth actually using is Hades, for certain fights (*cough* turks *cough*). A handful of summons are useful beyond that, combined with support materia.
While leveling they can help you access juicy on-hit status effects, or protection.
Ramuh - Paralysis (which is the only source if this status, apart from possibly items?)
Titan - Slow-numb (Same as above)
Alexander - Death Sentence
Hades - Multiple status effects. (Often used with Added effect in armor, creating the infamous ghetto-ribbon)
All Bahamut types - Shout element - The only protection (apart from shield?) in the game, against shout type attacks.
And these are just the more unique ones, there's also other status effects worth using.
Also, in regards to the chocobo.
Segabro posted this like 2 years ago, probably the same, still:
-) Gysahl - Attack = 220, defence = 32
-) Krakka - Defence = 220, attack = 137
-) Tantal - Magic = 220, MagDefence = 32
-) Pahsana - Magic = 137, MagDef = 240
-) Curiel - Speed = 240, Luck = 0
-) Mimmit - Speed = 64, Luck = 240
-) Reagan - Evasion = 240, MagEvasion = 0
-) Sylkis - Evasion = 0, MagEvasion = 240
His stats are fairly high in all areas to begin with, so for physical attacks I'd throw a Gysahl and Sylkis to reduce his defence and evasion. You'd maybe want to reduce his Luck too with a Curiel and using a Pahsana to reduce his Magic Attack if you don't plan to use magic attacks yourself.
(Yes, I'm super bored, semi-spamming this thread.
)
