They want bodies, or types, and Ornithopter is good for both in addition to mana and color fixing
For example, grading a first edition Base Set holo makes sense
Look for "Wave 3" reprints of sets like Prismatic Evolutions when prices usually dip by 15-20% before rising again once the set goes out of print
Hedron Detonator fills another niche, not only pinging opponents but also helping with the draw problem
To balance out creatures becoming more powerful, MTG has also introduced more effective removal spells over the years, like destroy spells, abilities to give creatures -X/-X counters, and the most powerful of all: Exile
The close-up photos above show that these two cards as well as the card on the sheet all have the same pattern of rosettes