My question relate to the extension of QWEB templates written in other modules, I found two ways to do it:

<template id="website.layout_footer_copyright" inherit_id="website.layout" name="Footer Copyright">

    <xpath expr="//footer" position="inside">
     
    </xpath>

</template>

and

<templates id="template">

    <t t-extend="DebugWidget">

        <t t-jquery="div.content" t-operation="append">

        </t>

    </t>

</template

By searching through the code in Odoo I found out that both methods were used, though only the second one is documented. Is there some situations where one is preferred to the other?