Yes.
It just means that
A) the 4G function has been enabled by the user;
B) it is actively provided by the network operator for that phone and is therefore operational.
The same applies to the “Wi-Fi Calling” signal 
which signifies that
A) the function has been enabled by the user;
B) it is actively provided by the network operator, the phone has a viable Wi-Fi connection and a data link has been successfully established over the Internet so that the function is operational.
N.B. - not all subscribers are eligible for Wi-Fi Calling. It’s only available if the phone is compatible, and the operator recognizes the phone, and provides the service.
The up/down arrows usually just indicate network activity, whether mobile data or Wi-Fi. When the phone has a viable Internet connection there will constantly be some traffic, however minimal, so these will be shown much of the time. Some versions of Fairphone OS don’t show them at all as some users find them distracting.
As stated above, the 4G Calling icon just shows that the service is available.
As explained by peci1, 4G Calling does not use “mobile data” as counted by your operator in GB (so no impact on mobile data consumption).
Having 4G Calling active may slightly increase power consumption but I think not much.
Having Wi-Fi connected, and / or mobile data, does increase power consumption.