Yes I have a service account of the 'flopped' Final Fantasy XIV I bought that copy years ago
And I have a service account of Final Fantasy XIV ARR.
When I have a closer look I see I got two tabs 1/2
1 = Legacy
2= ARR

When I press the picture/link Final Fantasy XIV ARR (from the link i posted initally) I assumed it guided me to my ARR service account (2) which it didn't, instead it directed me to my Legacy account (1).
It's very unlogical for me, because on the same page of the picture/link there is a link to Final Fantasy XIV (LEGACY)

This is how I accidently do a Subscription Renewal on my Legacy account which is dead for over a year....