GoKawiilIf you're concerned about data usage, you don't have to switch Lossless off everywhere. On your iPhone, open Settings > Apps > Music > Audio Quality. Here, you're able to choose separate quality settings for cellular streaming, Wi-Fi streaming and downloads, so you can keep cellular playback at High Quality while enjoying Lossless on Wi-Fi.
Downloading your most-played albums or playlists (while on Wi-Fi) is another option, especially if you have lots of free space on your device but a limited data plan. Lossless downloads take up more storage, but once the files are on your phone, playing them doesn't use cellular data. This is particularly useful for driving, since a USB CarPlay connection supports lossless playback — though your car speakers and road noise could mean you don't get the full experience.
Your listening hardware also matters. Bluetooth connections aren't lossless, so a Lossless stream sent from your iPhone to ordinary Bluetooth headphones will have its quality downgraded. The AirPods Max 2 support lossless audio over USB-C, but not wirelessly. Hi-Res Lossless has another requirement: an iPhone needs an external digital-to-analog converter, or DAC, to play sample rates above 48kHz.
Apple claims that the audible difference between AAC and lossless audio is "virtually indistinguishable." That doesn't make Lossless pointless, but it puts the cellular trade-off in perspective, especially when the final Bluetooth connection isn't at max quality anyway. Lossless is great when you can fully appreciate it, but isn't worth the data usage in other cases.