anyone used these recently,what was your thoughts?

Im looking to maybe getting three economy seats with basinett for our at the time we fly will be 8 months and myself and wife
Looking into this i believe singapore airlines allow to use these onboard,my other questions is are these compatible with the newer airlines like airbus etc etc,did this harness not come out a few years ago?

Our girl is already 18lb+ and who knows what she might be by the age of 8 months she is 4 months now,and going by what it says would be ok for a kid at 22lb maybe she will be this size or less by then im not sure,but would a kid at 8 months old be too young for this?

As we would be imagrating we would be taking a lot of luggage,etc etc and really dont want to be hugging around a car seat too,more so when its no use on the country we are heading to australia.

This harness sounds idea as easy to pack away and use,but my worries are will they fit the newer airlines,if not and we have booked an seat for our kid and not taken a carseat we will have wasted a seat on her as we can use a kid that young can we on the seat the way it is being too young,let me know your thought on this