If the Goldair lounge is anything like the standard of the one that used to be in the extra-Schengen area before the redevelopment, then it is unquestionably an enormous downgrade. It would regularly feature in lists of "worst BA third party lounge", and that's pretty stiff competition if you've ever visited the old one at RAK!
The reason for doing this is bound to be highly speculative.
Either you view it as creating more space so as not to have to deny anyone admittance on capacity grounds (it would be particularly embarrassing for A3 to turn away one of its own Gold members or Business Class passengers because the lounge was full of guests), and therefore conclude that the airline was acting favourably towards its customers
or
You feel the airline is deliberately trying to discourage Gold members from bringing a guest, to the extent that the alternative is so sub-standard they won't bother and A3 will save some incidental F&B costs.
In practice, I expect guests will be allowed into the A3 lounge at non-busy times because that incidental F&B cost must still be considerably less than paying for two people to go to the Goldair lounge.
I'd probably be charitable at this stage in thinking this is the airline trying to help, but what happens in reality might well change that view!