Subscription Only is the recurring model with one difference: the product can be bought only as a subscription. The usual one-time purchase choice is hidden, so every customer who buys the product becomes a subscriber. Use it for products where a subscription is the whole point of the offer.
What it changes on the product page
On a normal subscription product, shoppers see a choice between buying once and subscribing. With Subscription Only, that choice is removed — the product page presents the subscription as the only way to buy. There’s no one-time option to select.
When to use it
Membership-style products - Where the value is the ongoing relationship, not a single purchase.
Curated or replenishment boxes - That don’t make sense as a one-off.
Exclusive or members-only items - You only want to sell on a recurring basis.
How it differs from Subscribe & Save
The two are the same recurring model with the same discount and frequency settings. The only difference is that Subscribe & Save adds a subscribe option next to one-time purchase, while Subscription Only replaces one-time purchase entirely. If you want both audiences, use Subscribe & Save; if you only want subscribers, use Subscription Only.
You can switch this behavior on or off at any time in the option’s settings.