Smart-ID personal identification can be used today in Estonia, Latvia, and Lithuania. Anno 2023.

If you are an alien living in Estonia the options are:

• Residents of Estonia, Latvia, and Lithuania (incl. people staying here on the basis of a permanent residence permit) have a residence permit card. It allows you to create a Smart-ID account exactly as you would with an ID card: just follow the on-screen instructions. Your personal identification code is written on the residence card.
• If you are a non-resident, ie a person who does not have a local personal identification code, it is not possible to create a Smart-ID account in Estonia and Latvia. However, it is possible to register a Smart-ID Basic account with limited rights in Lithuania by visiting the bank branch of Medicines Bankas, don’t forget to bring your identity documents!

Additional data: https://www.id.ee/en/article/smart-id