Question---What is the benefit of isolating track?

If you are talking about breaking the layout up in to isolated sections it comes in handy being able to turn sections off for trouble shooting as well as lowering the draw on your system from trains that are standing in yards or passenger stations.  lighted passenger trains draw a lot of current. 

If you are using only DCS and Legacy you do not need isolated sections (blocks).  Having said that, Rick is absolute right about isolated sections, particularly yard or holding tracks.  If I turn on all of my yard tracks, the amp meter shows 8.3 amps with nothing moving.  Mostly because of 2 strings of passenger cars with incandescent bulbs, a bunch of cabooses and 15 locomotives “listening” for a signal.

While you are in the planning stage, you might want to consider whether you want to isolate some outside rail sections as activators for signals, crossing gates, relays or even a 16’ crossing guard.  These are easy while you’re building but a PITA after scenery is down (experience speaking).

Thanks guys, I purchased a Ross Turntable and I plan on using toggle switches to turn power/off on to each track off the the turntable so I won't have listening engines.  So essentially having isolated track vs just having wire drops does not effect DCS signal strength?  

My understanding has always been that the DCS companion and the late Barry Broskowitz both recommend that the mainline track (not just sidings) be divided into isolated blocks of 10-12 track sections each (regardless of overall length) for best performance; a consistently strong DCS signal; and to avoid DCS data packet "collisions".

Your mileage may vary, but that's the recommendation as I recall it.

Collision, loop, echo are possible on a continuous loop. Use equal braches.

For what it’s worth, I use Lionel’s Legacy/TMCC Control System and Control the entire layout with the electronic switches, ASC’s for accessory power of turnouts, and the BPC’s for Control Of 20 isolated blocks.  By using these electronic devices, I can walk around the layout and turn off any block, turn on any engine and utilize Conventional or Command because there are two sides to the BPC electronic switches. I utilized one block for my turntable area, and uses toggle switches to turn on/off the whisker tracks. Some times friends come over with post war engines and this allows both to mix with command trains running at the same time. Now, we use the IPad and IPhone to run trains to.  So, yes to having isolated blocks on your larger layout. I would imagine DCS can be operated similarly.