I saw lots of people saying that a hidden Zhonya’s Hourglass at a BF can only be played to the base because gears are not allowed to be played to the BF. If that’s the case, what is point of having the following rules? 811.1.d.1 A hidden permanent must be played to that battlefield. 811.1.d.1.a. This includes hidden gear, and overrides the normal restriction that gear have in only being allowed to be played to base.

Those people are wrong under the current rules — rule 811.1.d.1.a exists precisely to answer your question. A hidden gear is played to the battlefield where it was hidden, explicitly overriding the normal "gear only plays to base" restriction (Rules 148.1.a.1, 149.2). The "plays to base instead" claims come from older rules versions and older FAQ answers (e.g. FAQ #1533); the current Core Rules (2026-07-16) supersede them.

The catch is what happens right after: an unattached non-unit gear can't remain at a battlefield, so it's recalled to your base during the next Cleanup (Rule 457.1). So the full sequence is: play Zhonya's from hidden at that battlefield → it resolves immediately and its replacement effect becomes active → the next Cleanup recalls it to base, where it keeps working (since it doesn't target, its effect is global — no "same battlefield" restriction, per the Origins patch clarification).

So the rule isn't pointless: it guarantees the gear physically enters at that battlefield first, which is what lets it function during the current showdown before being recalled. The only accurate version of the "base" claim is that the gear ends up in base at cleanup — not that it's played there.