That way I don't have to worry about damaging roots by putting taller stakes in or damaging plants by trying to put a chunk of fence or cattle panel next to them, either of which should have been set up ahead of time. With the lean and lower trellis system, the vines can be grown to 20-25 feet long, IF you can keep them alive that long. You don't need a ladder to harvest. Branches are constantly pruned below where the maters are. That keeps air flow good and prevents foliage disease. It's what most of the market gardeners are doing these days. I'm tight on space inside the garden fence and this way, I can put tall posts outside the fence and string a wire between them up high to hang the vines from with twine. Just need some tomato clips. If it works out, I could be getting tomatoes until it gets too cold for maters.
Next 30 seconds of this video shows how long the vines can get. He's says probably 12 foot but it looks more like 15+ to me. https://youtu.be/J8L_x42RieA?t=303 Video is set in Sept at Univ of RI.