It is increasingly difficult to find two wheel suitcases.
If you are planning to stick to nice smooth airports and straight to transfer vehicles it is not an issue.
I have never personally owned a 4 wheel bag don’t plan to.
Others in my family do, however and these are the things that bother me most about the for wheelers.
They are poorly suited to rough terrain. A trip to Santorini will demonstrate the challenge of getting from your taxi to accommodation if you choose to stay in the cave style accommodation on the hill sides.
The pathways can be very rough cobblestones and two wheelers with good quality large inline skate style wheels are much easier and save carrying the bag.
Sure some 4 wheelers are coming with larger and more robust wheels these days but it is hard to beat inline wheels. In 2023 we travelled in Morocco, Seville and Lisbon. A of the old towns in the cities we visited had cobble or rough surfaces. You have to drag your bag behind you on these surfaces and while 4 wheelers have made significant progress in strength for this purpose small diameter wheels are not well suited to this terrain. Also when dragging your bag up over kerbs or staircases many spinners do not have protective strips against this type of abuse.
The other main problem is that four wheelers tend to occupy a lot more space in the overhead compartment or in car boots/trunks.
As more people are tending to move to choosing carry on only travel with maybe a 10kg limit you want to maximize the dimensions that will fit in the overhead. Two wheelers generally have much smaller exterior dimensions and if you are travelling in a small hire car will give you more likelihood of fitting the bags out of site in the back.
Two wheelers tend not to run away on their own.
Four wheelers that don’t have locking wheels need to be controlled on minor slopes.
This is rarely an issue with two wheelers which have a designed in brake.