Do you have an interest in expanding this to other cogs, for example Mod's [p]modset?

Yes. The goal is to slowly convert all of core to make it uniform.

For the sake of simplicity I though it would be best to split into seperate PRs per cored cog. (Hence I did warnings seperately) but if you want one big PR I can definitely do that as well.

So I'd like to state my official stance on this.

I don't think we should restrict functionality here, we should instead allow all commands like this to behave as both toggle AND setters doing the following.

 @embedset.command(name="global")
    @checks.is_owner()
    async def embedset_global(self, ctx: commands.Context):
    async def embedset_global(self, ctx: commands.Context, enabled: bool = None):
        """
        Toggle the global embed setting.
        Set the global embed setting.
        This is used as a fallback if the user
        or guild hasn't set a preference. The
        default is to use embeds.
        """
        if enabled is None:
        	enabled = not (await self.bot._config.embeds())
        await self.bot._config.embeds.set(enabled)
        await ctx.send(
            _("Embeds are now {} by default.").format(_("disabled") if enabled else _("enabled"))
        )

Seems we could go for some unification here on this field with setters and toggles. When discussing other unrelated things the idea popped up of unifying setting commands, in a way that they work both with a toggle and a boolean setter.

If I understand your comment correctly the thought is to have an optional bool argument that can set a value and otherwise default to a toggle? That sounds like a decent idea to me. I'd like to see more comments on this before I make changes to the PR though. Personally I am in favor.

I use this strategy often in Fox cogs, but sometimes no value is "reset to default" instead of toggle when it's not a bool but a multi select.

Overall I'm in favor.

I'm sorry for taking this long but I completely forgot about the suggestions here.