Cannot believe some are defending 128GB still, this is like when Apple were still shipping iPhones with 8GB all over again. I have a 128GB MacBook Pro 13" as one of my play Mac's. I've had to delete Microsoft Office off it because I could not update XCode because of not enough free hard drive space and I only use this Mac for Xcode and installed Office out of habit. The Big Sur installer is 12GB which is 10% of the total storage and needs 16GB free to install.
If it was 512GB as the base MacBook Air and a special 256GB been made available for education at lower cost that would have been fine, but 128GB on a premium device in 2020 is pathetic unless these were being sold at Chromebook prices. You cannot use the 'cloud storage' argument, Apple give managed edu apple ID's 200GB of iCloud storage, Mac has no selective Sync for iCloud , so Teacher has 128GB Mac and 150GB in iCloud, what do you think is going to happen when they sign in?
Use Microsoft OneDrive? yes that client has selective Sync and files on demand but teachers don't want to mess with selecting what folders to sync , and if you use files on demand it will keep slowly using more space up as it caches stuff and won't be long until you as Sysadmin cannot push the latest version of Excel out without it failing on these devices due to lack of disk space, like I have had this week on some 2013 MacBook Air 128GBs we still have that are close to end of life for us.
The only place I could justify 128GB in a Mac is in an IT Lab with folder re-direction to a home share so there is zero user data stored on the device, but again for the cost of a Mac, 128GB should not even be an option.
Also think ahead 3 years... you might be able to just about get by with 128GB now with some compromise, but in a few years? Yeah..... right. MacOS will be bigger, Word will be bigger, Garage Band will be bigger.
and if you think well 128GB is fine if you just want a device for web browsing, yeah that's true, but go look at what happens when you give kids laptops over on reddit in r/k12sysadmin and then think about how much Apple will charge for a new keyboard on a MacBook Air once the little angels have pecked keys off.