Best way of Grouping Functions into Tags?

Say I have two functions namespace:function_1, and namespace:function_2.
If I wanted to group them into a tag like this:
{
    "values": [
        "namespace:function_1",
        "namespace:function_2"
    ]
}

... should I put them in my namespace or the minecraft namespace? I've tried both ways, and they both seem to work.
<namespace>
└──tags
   └── functions
       └── my_tag.json <-- here
minecraft
└──tags
   └── functions
       └── my_tag.json <-- or here
       └── load.json
       └── tick.json

Just started learning about tags after wondering what there were for for way to long lol. I'm just curious on ways I can use them now.