Suppose you have to travel, and for one reason or another you reckon 100% charge will be necessary or at least advisable.
You could charge to 100% at night and leave it plugged in. But is there any advantage to charging to 90% during the night, and topping up to 100% in the morning?
My logic is, there could be a few factors that apply.
a) Perhaps electrode degradation happens not only when charging, but also when the battery sits at full charge. Keeping the time it sits at 100% could have some effect.
b) Keeping the temperature down is good for batteries, especially towards full charge. So letting the bulk of the battery cool down, then putting in the last 10% could have some effect as the battery would start cool and then gradually warm up, maybe not to as hot as if you did it all in one go.
c) A warm battery is better for driving, so they say. So doing the last bit of charging in the morning could leave the battery nicely warmed up and ready to go, whereas doing it at night would give you a hot battery when you don't want it, which would be cold by the morning. Also, having only just now charged up to 100% there might be a joule or two more in there.
d) Of course, if it's hot/cold out there you can cool/heat the cabin while it's charging too.