Should we not modify the settings of the default BigNumber instance?

[overcat]

Describe the bug
See https://gist.github.com/Shaptic/5ce4f16d9cce7118f391fbde398c2f30?permalink_comment_id=4873892#gistcomment-4873892

What version are you on?
v10.0.2

To Reproduce
N/A

Expected behavior
Wouldn't it be better if we could not affect the settings of the default instance?

import {BigNumber} from "bignumber.js";

const SDKBigNumber = BigNumber.clone()
SDKBigNumber.DEBUG = true
try {
    new SDKBigNumber("invalid")
} catch (e) {
    console.log("error")
}

// This will not affect the settings of the default instance, so no exception here.
console.log(new BigNumber("invalid"))

Additional context
N/A