The 24GB unified memory is a really nice upgrade (the M1 MBA has 8GB upgradeable to 16GB). The CPU/GPU upgrades are predictable and wlecome but the memory is huge. A lot of development isn't CPU bound but is memory bound or at least can really benefit from more memory. This upgrade makes the MBA an entirely viable dev machine for many workloads. I have a MBP (Intel) but it's expensive. Getting a viable machine for $1…
For web dev the base model (8GB RAM) MacBook Air M1 is a viable dev machine - makes the maxed out i7 MacBook Pro I had from work feel sluggish in comparison.
If you can guarantee you won't need more, sure it's plenty viable. If you can't make that guarantee, you need to remember there is no upgrade path. You will be selling the machine and buying a new one.