In Europe, including the UK and EEA, there is the eIDAS regulation, which outlines the requirement for eSignatures (amongst other things).
In order for a signature to be recognised, it has to meet one of three trust levels
1. Electronic signature: this is basically something that puts a distinguishing mark on a file.
2. Advanced electronic signature: these use cryptography according to the specifications set out in the regulation, but anyone can make them. There are some requirements about how a person’s identity is linked to their signature.
3. Qualified electronic signature: these are advanced electronic signatures which have been produced with a recognised trust service provider. Each country has a list of trust service providers, and each other country mutually recognises their trust lists.
It is a bit more detailed than that, but in general, simple transactions can pretty much use any electronic signature (but this varies from jurisdiction to jurisdiction. The uk generally doesn’t need anything fancier than docusign). In order for something to be completely watertight, it needs to be a qualifying electronic signature.
In order for these features to be useful in Europe, google will need to meet the requirements of the regulations, and specify a trust level.