What are drawbacks of using aura design tokens in lightning web component

Question

Tokens

<!--tokens-->
<aura:tokens>
<aura:token name="testBgColor" value="#e7e7e7"/>
</aura:tokens>

Aura Wrapper

<aura:component description="auraWrapper" implements="forceCommunity:availableForAllPageTypes, flexipage:availableForAllPageTypes">
    <c:lwcTest/>
</aura:component>

My question is related to loading aura component or in other word wrapping up Lightning web components in aura component. Won't loading aura component affect performance in any way? If I don't want to use design tokens mechanism, what are other options to have a common shared css? I understand there is no mechanism for having common/shared css because of shadow dom.

lwcTest.html

<template>
   <div class="test">Hello World</div>
</template>

lwcTest.css

.test { background-color: var(--lwc-testBgColor, red); }