My first question would be "why not microchip?" collar with tags are easily removed or lost. I've even heard of tattooed ears being cut off - that's why they recommend that you tattoo on the inner thigh.
The microchip is a good way to settle disputes and to prove ownership IF NECESSARY. That doesn't meant hat vets or even Animal Control (sadly) will scan for them. Here, our animal control doesn't routinely scan even though they ONLY collect dogs without collar/tags.