I don't know their reasoning, but it may have been to align that part with common oil filters in Japan. Honda motorcycles and other Japanese makes of motorcycles use a metal can with a replaceable filter element. That type has been used for at least since 1970 on 'cycles.

Both types filter well. The cartridge type is messier to change, but has the advantage of providing a look inside the filter can to get a view of what has been collecting.

I prefer the metal can over a plastic one.

In Japan, a number of engine design features were first tried on motorcycle engines before transferring to automotive engines. For example, 4 valves per cylinder first appeared in a motorcycle enigne. Yahama went as far to make a 5 valve cylinder and then settled on 4 valves. The problem of designing machinery to actuate multivalve per cylinder engines was worked out on a motorcycle engine.

my oil filter socket wrenches always seem to slip. the fact that the camry has a plastic housing is cause for concern. the cheap stamped steel sockets are tapered so they are loose to begin with. the dealer wanted $59 for a 64mm socket. and $50 for a new plastic filter housing. its easy enough to find a 65mm socket but harder to find a 64mm socket. they are online of course.

You should be able to find a socket at Sears for less than $50. Buy the 6 point, and not 12 point socket for best grip. Buy the Craftsman brand.

Other places where you may find suitable sockets are Autozone, NAPA, and Advance Auto Parts. NAPA may be pricery than the others. The Snap-on brand is good quality but with top price too.

If you are having trouble getting oil filters off, it may be those were put on too tight. Follow the tightening instructions on the filter carton or service manual.

For most spin-on filters, after the seal makes contact and gives a slight resistance, tighten another 1/2 to 3/4 turn. The new gasket swells upon contact with hot oil and further tightens the seal. A can with replaceable cartridge and center bolt will be different and may need a bit more tightening, but it too can be over tightened.

The torque on the cartridge style filters is generally stamped right in the filter cap. Typically it will be listed as 25N/M or about 18ft/lbs.

There are a number of reasons that the change to cartridges is being made. It reduces the oil that gets put into the garbage dumps because they are easier to drain, and many simply get incinerated. Plus we aren't throwing away a metal can with each filter, meaning less waste.

It also allows the auto manufacturers to have control over bypass valve opening pressures, and anti-drain back characteristics for quicker oil flow on cold starts.

it does use 0w-20 oil so i assume that flows pretty well when cold.