It's interesting that SmartCharge gives an option to set a maximum SOC. The choices are 55, 70, 85 and 100. This could imply that Honda recognizes that some people prefer to charge to less than full in order to (potentially) reduce battery degradation. Although I'm not sure why they limit it to those four choices, maybe to make the interface simpler. But then again SmartCharge lets you set start and end times to the minute, for example 4:38 PM, which seems a bit overkill.
But there are a couple of other reasons that I can think of that someone may want to charge to less than full. Some people have issues with the engine starting shortly after they leave home if they have a downhill or stoplight close to the house, due to the inability of a full battery to store regen. But I would think setting it to 95% SOC would take care of that, setting it to 85% forgoes quite a bit of EV miles just to solve the startup problem. But that's the only choice available.
Another situation would be if someone can charge at work for free, so they want to maximize their charging at work. Let's say someone's workplace is at a distance that can be driven with 60% SOC worth of battery power. If they leave home with a full battery, they will arrive at work with 40% SOC remaining. They then charge for free to get from 40% back up to 100%. When they arrive back home they are down to 40%, so they charge from 40% to 100%. So not counting any other driving, each night they are charging 60% worth of SOC at home on their dime. But if they charge at home to only 60% SOC, then they would arrive at work with 0 EV miles, and they could then charge from 0 to 100% for free. They would still arrive home with 40%, but since they are only charging to 60% they only have to add 20% worth of SOC. That's 40% SOC a day that they don't have to pay for. Whatever the conversion happens to be for them from SOC to kWh to $$$, it's a savings that would add up over time. Although to do this in SmartCharge they can't set 60% as a maximum, they would have to choose between 55% and 85%, reducing their potential savings. Again I'm not sure why SmartCharge limits the maximum to four choices.
So what did Honda have in mind by allowing people to set a maximum SOC when using SmartCharge? Who knows, I guess add it to the mystery list which is already pretty long.