Turbavykas,
Yes this is true, you may, depending on circumstances, need a higher CAT. This is why you see the A330 series C or D, and a 737-700 C or D.
On final, you may not want to go full flaps to get below the CAT speed and use a higher one.
Turns include a max bank angle for the aircraft, which varies significantly between aircraft. The FD may limit the bank angle far below the criteria bank angle, so you may have to use a much larger radius.
While the 8168 doc states that, the design criteria is based on segment. For CAT C example, the max IAS cannot exceed 140/141 kts in the final approach segment. Turns to final, such as with RNP-AR, complicate the issue, as the criteria forces the final approach CAT speed through the entire turn. This is why you see such large turns to final (and while the ac can easily bank the turn at 20 degrees, you will see the ac bank about 5....)