If 'At the end of the turn during which fusion took place...', or similar requirements are listed in your Digimon's fusion requirements, they will still apply even if you had made this card directly appear from your hand through the use of Option cards
I don't personally use it either as it falsely creates the idea that these have a different rarity set than other Secret Rares, and there is little evidence to support that
For one thing, the nostalgia factor is in play with this Special Illustration Rare
I think that this card is especially great when playing lightning rod commanders like Prosper, Tome-Bound that are in colors that lack many good ways to protect them from being destroyed
If you're ready to build a competitive custom deck, you'll find you need an awful lot of singles that just aren't present in this starter deck
The improvement over the A750 is similar