Test the brand-new spend() extrinsic

The Polkadot Fellowship has introduced a new spend() extrinsic.

This proposal aims to raise awareness about the new features it supports and to test it out by tipping Alice und Bob 69 USDT on AssetHub.

The new spend() extrinsic has been introduced with the Polkadot Runtime 1.1 upgrade. It supports:

• multi-asset Treasury spends, e.g. DOT, USDT, USDC, etc...
• from an XCM multi-location, e.g. AssetHub
• to be paid out at a specific block

This new extrinsic makes a lot of things possible:

• instant payments instead of waiting a spend cycle of up to 24 days
• paying proposers in USD stables to remove exchange rate risk
• setting up a payment plan of monthly payouts by batching multiple spends at estimated block heights
  • and even canceling scheduled payments

This proposal is based on the information provided in this forum post and this instructional guide. It is intended to test if the extrinsic works as described. During the test, it was already discovered that the instructions are not exactly correct, as Polkadot.js tries to help the user by having value fields taking "DOT" values that add 10 decimals under the hood, which interferes with the GeneralIndex field of the assetKind location and the amount field. A wrongful proposal 707 was the result. This proposal should have corrected values. But further errors might be possible since this was never before tested in production.

I suggest sending 69 USDT because it's a funny number and it's related to Bitcoin

The call works as follows

The V3 AssetKind contains a V3 MultiLocation pointing to Parachain 1000 -> AssetHub. The AssetID is a relative location inside AssetHub pointing to PalletInstance 50 -> assets, GeneralIndex 1984 -> USDT

The amount is 69_000_000 (USDT is denominated with 6 decimals)

The beneficiary is Polkalytics, the company account of Alice und Bob