Well, in essence yes. But I have seen enough mishandling and homegrown stuff of custom date-time calculations that this could get interesting. I suspect that there are a lot of systems where the TZ database is never updated which at least will result in shifted displayed local time.

Also, it is fun to get data from old programs and also from userinput where the actual offset has to be guessed from the timezone. And if that conversion data is old, fun is had. It does not matter how time is represented internally in this case.

Every time this topic comes up I wonder how many computer systems this will break. Maybe we find out soon if this is really realized.