Haha I've had the same boring navy blue potty for 10 years!

DD preferred the potty because she could sit on it and play/read and scoot on it around the house, which you definitely can't do on a big toilet. She started using the toilet when we moved the potty out of the loungeroom (too many times she'd spill it on the carpet) into the laundry, and apparently it was so unacceptable in the laundry she refused to use it.

She completely freaks out if we go somewhere that the toilet insert doesn't fit the toilet. We actually have more luck just holding her on a big public toilet, but she'll only poo with the insert. So we try not to travel to avoid a child that can scream for HOURS because she needs to poo but won't at a strange place.