Reason for use of defaultOp in UserOperationBuilder

[sushisilence]

Hello team,

What is the purpose of defaultOp in the UserOperationBuilder?

userop.js/src/builder.ts

Lines 28 to 38 in 1d9d0e0

	export class UserOperationBuilder {
	private defaultOp: IUserOperation;
	private currOp: IUserOperation;
	private middlewareStack: Array<UserOperationMiddlewareFn>;
	constructor() {
	this.defaultOp = { ...DEFAULT_USER_OP };
	this.currOp = { ...this.defaultOp };
	this.middlewareStack = [];
	}

I'm asking because in SimpleAccount.init():

userop.js/src/preset/builder/simpleAccount.ts

Lines 89 to 98 in 1d9d0e0

	const base = instance
	.useDefaults({
	sender: instance.proxy.address,
	signature: await instance.signer.signMessage(
	ethers.utils.arrayify(ethers.utils.keccak256("0xdead"))
	),
	})
	.useMiddleware(instance.resolveAccount)
	.useMiddleware(getGasPrice(instance.provider));

A default message is being signed, and some defaults are being set. For a normal EOA an extra signature is okay, but if an MPC/Hardware wallet is used, then an extra signature is not ideal.

Is it possible to skip signing a message in the SimpleAccount.init() method?
Thanks!