DS turned 2 a couple of weeks ago, and has only just taken an interest in my iPad. I've put some games on for him with pictures of different animals, vehicles, musical instruments etc and sit with him and talk about what they are. He also likes to watch videos of himself with his grandparents and he face times my parents sometimes. He also likes books, drawing, playing outside and making a mess - typical toddler things.
I don't get why a toddler using technology is a problem, provided they get to do a whole variety of things and aren't just left with a tablet and ignored.
I've found it useful to amuse him when it for a meal or when I need to do household tasks, or when I just need to sit down for a few minutes without running after him!