You've both touched on really good points, and these points have actually led to controversy and some rather bitter exchanges between thread posters elsewhere on RC and on other marine hobbyist sites. It really is a clash of paradigms!
In the planted method, one depends on the plants much much more than nitrifying bacteria to "cycle" the tank and ready it for animal introduction. Since the plants (marine macros, too) absolutely thrive on and prefer ammonia, they scavenge it out of the water quickly and before any nitrifying bacteria really have a chance. Understand we are not talking about little wisps of green and red, but fat root bulbs and generous clumps of plants installed in the substrate and attached to decor on day one after filling the tank with water. In a FW set up, the water need not be RO/DI or even dechlorinated if there are no animals to worry about, and how many gardeners bother dechlorinating before watering their plants? We don't care about the chlorine killing bacteria, because we're not going to be depending on them, anyway. In the meanwhile, of the fw bacteria being suppressed are the nuisance cyanobacteria and single cell micro algae, too. Over a surprisingly short period of time the chloramine is broken down, as are the chlorine and fluorides and nitrates, and copper ions through metabolic and photosynthetic processes in the plants tissues and via oxidation into ammonia compounds (more plant food!). You just don't end up going through the toxic spike levels of ammonia to nitrites to nitrates like you do with bacterial cycling. The bacteria are there (if you dechlorinate), but in the much smaller concentrations that they occur in in the wild. The plants (and, yes, macro algae too) represent instant biomass for processing nutrient toxins, thereby rendering the dependence on nitrifying bacteria moot. Starting a marine tank from day one with macro algae and/or vascular plants in display and/or refugium will offer the same results. You will also be preventing the annoying micro algal blooms that otherwise occur in new tanks. I would warn that macros, being just huge highly evolved single cell algae are as vulnerable to large concentrations of chlorine as are micro algae, but they will not be harmed if you decide to forgo RO/DI water (most salt mixes have disodium sulfate dechlorinator built in to the mix, anyway, so one would be somewhat challenged to set up an experiment to see if any macros could survive "raw" tap-based saltwater mixtures).
Some FW hobbyists are fascinated by the use of live sand and live rock in reef aquaria, and are getting great results collecting the freshwater equivalent from clean, healthy ponds, lakes and creeks. This added biodiversity makes the plants and fish even happier, and they can add quite a few more fish safely within 2 weeks of starting a tank with these methods. As it is usually done, though, a prepared substrate is carefully set up using dry gravel with a layer of iron-rich laterite gravel between, and plugging in fertilizer tablets or bits of fish food to rot and provide ammonia for initial plant root growth, or a few small fish or snails are added as soon as the water cloudiness subsides, along with setting up a CO2 diffuser kit.
When I set up my 2 new nanos, on day one I had macro in both. In one tank, the cured LR shipment had been delayed in transit and suffered great die-off; the huge clump of Chaeto I floated in there helped remove the stench within days. The tank achieved stable params two weeks later. In the other nano with a smaller mass of Chaeto and much smaller lb-per-gallon percentage of shipment-damaged rock, there never was a detectable cycle. I have done this recently with great success, and have done this for many years in FW, and even did this in marine as a kid many years ago, collecting substrate and marine grasses and Caulerpas to set up my tanks before collecting my fish, mollusks and anemones (boy! I just followed what I knew from school - had I known then how weird and scary this would seem to some folks 30 odd years later!).
