In my experience, getting an eSIM is usually cheaper than the airport SIM card plans, but often there are cheaper plans available when you get to the city. In any case, having both options is nice!
I think it depends on how you define “developing countries”!
I’m currently in Thailand and I got 6 GB for about $2 total (50 baht for the SIM with 3 GB for 3 days, another 20 baht top up for another 3 GB / 3 days). I did use eSIM for about a month before that though (I just wanted a local number to order some stuff from Lazada).
Another example (also from Southeast Asia, FWIW): Malaysian SIMs are also cheaper, though topping them up is painful so I’d personally stick with an eSIM there.
