No point getting an M3 MBP when an M3 MBA exists.
...but it doesn't. The M3 MBP has been available for about 4 months already and a new Air release date hasn't even been announced yet. Anyone who wanted a new MBP either already purchased it or if they weren't convinced to buy one until now then if a new Air convinces them to finally make a purchase Apple won regardless. Once you buy an Apple device and are hopefully happy with it you might keep buying them and recommending Apple devices to friends and family.
No point getting an M3 MBP when an M3 MBA exists.
For me it's the other way around, the MBP has the superior hardware. The Air is less heavy and that's about it.
when doing intensive work that takes a few minutes of cpu I wouldn't really care or notice if it was 20% faster.
It's the same for me, yet the Airs max out too soon with upgrades to allow me to get away with it. It doesn't have 32GiB of RAM which is the bare minimum my workflow requires, and 2TB of storage are way too little for a main device. The only reason I left it at 4TB were the high costs of the 8TB option. As a secondary device on the go the Airs are plenty yet if I have to get 2 devices it would cost more money overall and be more inconvenient than a single 14" MBP that is mobile enough yet doubles as a desktop workstation in the office. The one external monitor limit of the base SoC would add to the inconvenience.
Now more than ever I'd choose a 14" MBP over an Air since its footprint is just small enough to carry it in a backpack daily yet its performance is beyond anything this form factor allowed for in the past. 10-15 hours of battery life on a 128GiB RAM workstation laptop with this form factor were simple impossible until Apple Silicon came along.
There were so many customers asking for Apple to stop making their products thinner with less and less ports and to make the Macs actual Pro devices again. Now that Apple is embracing that I am here for it. In the past I had a MBP, a Mac Pro, another Windows workstation, and a 12" business laptop. Now all these have been replaced by a MBP.