Yes, it makes the running of the trains more reliable. I am surprised your blocks are such that you need to split the rails on EVERY piece of track. Note that it is an impracticality when you get to the points ...

You can use other types of sensors to avoid cutting the connections between tracks. The main advantage of the Marklin 3 rail system is its superior current conducting properties, and this is negated when the tracks are isolated in this way. It also means that if you are using non-Marklin wagons with original 2 rail wheels they wont be detected.

For trains detection many people use optical sensors or magnetic reed switches, especially in the 2 rail DC world.

Consider a Köf III running all alone. Three wheels without traction tyres for good contact.
On a contact track there is a 50% chance that only one wheel without traction tyre will be left on the "ground" side with two wheels on the "dead" side. When used with s88, the famous diode trick can improve contact in such a case.

You need three feeder wires if they are isolated, only two if they are connected.
It's easy to cut them, it's more complicated to connect them.
For C track without centre rail, they cut the bridge at the factory.

K track comes isolated (most pieces except feeder tracks and some turnouts), C track comes connected.