Data Generation and Query Analysis Finding

Question...is the data generated with geodetic and queries are using cartesian and it's not reflective in accurate query analysis. For example, in Oracle Spatial...if I use your latitude and measure it's 41 km and not the 50 km.
SELECT sdo_geom.sdo_distance (
sdo_geometry(2001,4326,sdo_point_type(0,34.8697,null),null,null),
sdo_geometry(2001,4326,sdo_point_type(.45,34.8697,null),null,null), .005, 'unit=km') AS distance_in_kilometers
FROM dual;

41.1446555135459.

--At Equator yes...the .45 is correct and reflects 50 km
SELECT sdo_geom.sdo_distance (
sdo_geometry(2001,4326,sdo_point_type(0,0,null),null,null),
sdo_geometry(2001,4326,sdo_point_type(.45,0,null),null,null), .005, 'unit=km') AS distance_in_kilometers
FROM dual;

50.0937708570127