Why would anybody use NTFS? btrfs ftw. Also all EFI partitions are FAT. And lastly, if you want a USB stick to be portable across operating systems, FAT is still the way to go
Btrfs with compression can substantially "increase" capacity of your USB stick. IIRC I managed to fit 20-30% more data on 64Gb stick than its maximum capacity!
Everything uses FAT32. ATMs, the fare machine on transit systems, the sorting system at your post office, traffic lights, nuclear power control systems. Literally everything that isn't a Unix, MacOS, or a Windows machine uses FAT32. All that stuff has worked for decades and will probably keep working for decades more.