Losing your Scrolly tag does not trap you behind your own block. Scrolly has an emergency unlock built in for exactly this, and the app keeps running on its own until you replace the tag, so your settings, schedules and progress stay where they are.
You lose the daily switch - the tap that turns blocking on and off. You keep everything else: your account, your blocked-app list, your schedules, your statistics and your streak. Replacing the tag puts the switch back without redoing any setup.
Spare tags are sold individually on the store, so a lost one is a small replacement rather than buying the product over again. Some people buy a second one on purpose - one for the keyring, one that stays at home.
The tag is made to go on a keyring, which is the practical answer: it then travels with the one object you already never leave the house without. A carabiner clip rather than a split ring makes it easier to move between a bag and a set of keys.
Portability and difficulty are in tension. A tag in your pocket goes everywhere with you, which also means it is always within reach when you want to unblock something. A blocker fixed to a kitchen counter is harder to beat precisely because walking to it is annoying, and useless the moment you leave the house. Carrying it and leaving it behind are both valid strategies - the device supports either, and which one you pick matters more than the device itself.