Ditto

Nope.

The only use of a Ditto is for a very complex prestiging strategy. Ditto with 15 attack, 0 def and 0 stamina IVs at a higher level would tansform into a high CP Dragonite with low HP for example, and you could use a lower level Dragonite or swap to a Ice Attacker to easily prestige against him.

Dragonite was just a example. You can use any mon that has a move that is SE or neutral against himself and also has more STA than Ditto. Not very practical, but could be a fun way to play.

In the future they can be useful for breeding.

i'm keeping a few but i'm not "investing" in any of them.

I have 2 87's, don't use them, but I know at some point they'll be important w breeding. Just save them for now. I have 400+ ?.

Ditto with 15 STA IV is worth investing in.

I've got a 98% IV Ditto I've got near maxed out (I think it's at 36?), for the novelty of putting him in a gym and hopefully making somebody crap their pants when he transforms into an OP version of their attacker.

The only thing I am willing to invest is a little pack space, to save some good IVs and various level ditto.

Nope purely breeding.

How does ditto help with breeding? I have a 96 L25.