I bet there will be some drawback, such as it runs macOS, but can only install/run apps from the Mac app store.
It is unlikely Apple would be running some 'forked' macOS. Limiting to the AppStore isn't not going to give them managed "Chromebook" like application management limitation abilities. there is tons of 'junk' in the appStore.
the "draw back" is going to be the A18Pro.

.
Probably can only provision one "high speed" (10Gb/s) USB-C port. So either a 'one port wonder' (like MBA 12" and iPad) or second port is just the USB 2.0 needed for a keyboard case to work (in iPad context). ( or possibly a USB hub to the just the one 10Gb/s provisioning lanes that get gets 'split' between the two ports. So would be shared bandwidth. ). A USB 2.0 only port would definitely would be seen as a limiter.
Extremely good chance that the A19Pro is simply lacking in respectable laptop/desktop provisioning I/O capabilities. No Thunderbolt. (e.g. Macbook 2015)
decent chance no MagSafe. So if have just one port and need to charge it .... no more ports left. (unless run through and external power hub). In short, designed around not needing to plug in anything 99% of the time.
The RAM will likely also be capped. (maybe just one single capacity). the SSD will be much slower than an M5 family SoC (but 'fast enough' for casual usage.). Both of those are constraints imposed by the A19Pro SoC.
Weaker GPUs relative to M5 family and fewer GPU cores.
Non-A18Pro stuff.
Just one color ( to keep SKUs down and inventory cleaner ).
Fewer SSD options ( to keep SKUs down and inventory cleaner).
Recyle. 2020 MBA 13" case, screen , camera. ( old stuff with an even more limted chip inside).