The narrow trail: mobile
It works on a phone. It is not where you want to do the careful work.
Tor Browser for Android is real and it opens every plate in this atlas. But a phone is a narrow trail, and some of the careful work is harder to do on it correctly.
What works on mobile
Login, the anti-DDoS queues, captchas, browsing, ordering, messaging, disputes. The markets function on a phone the way they do on a desktop. For reading the atlas and doing routine things, the mobile browser is fine.
What is harder
Copying a fifty-six character onion address is fiddlier on a touch screen, and truncating one by accident is easier. Verifying a PGP signature is more awkward because the desktop tools are more capable. And the mobile anonymity set is smaller, which means a mobile browser stands out more than a desktop one.
The iOS problem
There is no genuine Tor Browser for iOS. Apple forces every browser onto the same underlying engine, which limits how much a Tor-focused browser can differ from a normal one. Third-party apps exist and route through Tor, but the guarantees are weaker. If you have the choice, use Android or a desktop.
The rule
Do the setup-heavy work, first registration and PGP verification, on a desktop. Do the routine work wherever is convenient. The narrow trail is fine for walking, less so for the parts of the crossing that carry the most risk.