The 365 versions would give you continued updates for as long as you are subscribed, and will continue to be usable in the future.
The stand alone versions, would eventually stop getting updates and eventually stop working all together.
The 16.26 version I believe belongs to the 2019 stand alone version of Microsoft Office, which is the current one, and would continue to be supported for the foreseeable future however.
However, by using the 365 versions from the App Store, you are essentially negating whatever you paid for the 2019 stand alone version. I other words, by paying for the subscription and the 2019 version, you are essentially paying for the same thing twice, and choosing not to use one.