They're all much smaller and probably work better than the ones kids were forced to wear at the California School for the Deaf back in the 1960s when I worked there. Those hearing aids were about the size of a digital camera and weighed at least as much. Kids would wear them strapped to their chests in harnesses and connected to ear buds by wires.
The kids hated them!
In the first place, they amplified all sounds equally. Most deaf people have some hearing in the very high and very low range, so the hearing aids would make those sounds loud, but the children still wouldn't be able to hear things clearly, if at all, in the voice range. Since many educators working with deaf children still tried to force them to learn to speak and read lips the hearing aids were supposed to help with that.
In the second place, it was too late for most of the children who had been born deaf and never heard speech to learn to understand it by then. The brain has a window of time starting at birth when it is prepared to learn language. That ability decreases over time and is extremely limited in older children.
The kids would do everything possible to "lose" the uncomfortable and irritating hearing aids by hiding them, tossing them in the trash, or damaging them so they wouldn't work.
I've heard adults who are loosing their hearing complain about problems with hearing aids but their inconveniences don't come close to the nightmare those old "body unit" hearing aids used to be. And hearing loss is certainly not anything to be ashamed of.