I used it on a flight to Thailand with my then 20 month old. He was a big boy and I was worried beforehand whether he would fit, but he did and it was so useful being able to put him down when he was asleep so we could have hands free to eat and look after our older child. You also have space underneath to put water bottles, toys etc.
The only thing was you can only use it when the seatbelt sign is not on so we had him waking when we transferred him, whereas if we'd kept him on our lap the whole time he might have slept through. But he was a bit of a heavy lump to hold by that point, so worth it overall to us. Only you will know how much of an inconvenience having your little one in someone's arms the whole time would be, and how happy they'll be to sleep in the chair. He did look so cute tucked under a little blanket asleep on it though, and you can use both hands to take pictures of the cuteness. (Or one hand to take the picture and the other to eat chocolate without little one grabbing for it)