Dope does not benefit from being immersed in water for extended periods of time. This is why so many DWC, aeroponic, or ebb systems are fraught with problems. In a standard flood and drain table, rez problems are not generally a problem. Proper drainage is a basic tenant of farming be it dirt or hydro. The idea of a fast filling and draining system, most any system whether it be dirt, flood and drain, ebb, or aero. is or should be strived for. Now that is not to say that you cannot grow in a slower filling/draining system. Or a system where water is laying stagnant. Obviously it is possible but the longer your roots are immersed the more prone to root problems your plants are. So if you can achieve a full flood and drain in less than half an hour it is possible you can flood them more times a day beneficially. Another benefit to running 3/4 lines is you can run fewer main hoses and have more pots connected to less mains and still achieve fast filling/drainage. thereby allowing you to free up valuable floor space that would otherwise be cluttered by a spiderweb of 1/2 inch lines.
Yes as hellraizer pointed out you may very well have more water in your lines tween waterings but if you elevate your pots this can be remedied easily. I raised my buckets 1/2 inch and my lines have less than 1/4 inch of water in em while in drain cycle. I run 10 inch netpots in 2 gallon buckets and flood 15 pots fully in just under 15 minutes. Fed only by three 3/4 main hoses.(each main hose has 5 pots connected to it) The entire flood/drain cycle takes bout 1/2 hour. I just completed my ebb expansion for my mums and I can see that after being placed under 1000w they will benefit from having a second watering a day. I plan on flipping 15 moms every 4-6 weeks. With space for 30 mothers in flower I will have two 15 plant harvests in my room.This will allow me to keep strong vibrant mothers to clone off of and keep two 1000w lights on in flower over my ebb sys as well as keep plenty of 8-12 inch clones for my 8x8 sog.