Battery life on Intel-based Macs is great, but not miles past Windows-based laptops. With the ability to control not only the software and hardware, but also the platform, I suspect we'll see big battery life gains from new Macs, whenever they arrive. Consider waiting.
You use Boot Camp to run Windows on a Mac
I can't imagine this will be officially supported on Arm Macs, so either buy now or wait for more info. Then again, plenty of Windows systems run on Arm platforms now (how well they run is, however, arguable), so it's not impossible.
You're a Mac gamer
You are? Really? I think this spells the end of the current weak attempt to get more traditional PC games on Mac via Steam and other platforms (so, no, I'll never get Fallout 76 on Mac). But the ability to run iOS and iPadOS apps easily, along with game controller support, could make future Apple Arcade games more ambitious -- I'm looking at you, Beyond a Steel Sky!