The other difference is the degraded frequency spectrum because you transmit “client-only” packets everywhere,
this causes interference with others and you too can receive more interference.
If you need simply poit-to-point with gigabit ethernet use two SXTsq 5 ac, if the distance is under 1km use the Wireless Wire nRAY kit
You can use the RBSXTG-5HPacD as a client. Just set it to “station bridge” or any other client method. It will still have the wide angle.
However normally you don’t need that level 4 RouterOS license to be a client. There is no specific client model in that hardware family (anymore, the RBSXTG-5HPacDr2 is discontinued, it’s in the archived hardware list). A SXTsq 5 ac is a perfect fit as client. (There is no SXTsq5 ac AP version, but for point to point 2 SXTsq 5 ac will do , one in “bridge” mode, other in “station bridge” mode. “Bridge” mode is like an AP but with only one possible client, and only requires the level 3 license)