There is no clear separation between honesty and lies. Instead there are honesty, mild lies, ordinary lies, outrageous lies and acting. Honestyy is a way to get things work well. It is a way to gain position, influence things even otherwise and form better bonds with people and prevent others from hurting you.
People want some information to be a ground for their actions, and if they have noticed that they can rely on your information, it is likely that your view get heard and taken into account. So if you have points that are worth something, you gain position via honesty. It is also easier for others to take you along if they can be sure about what they get.
Being honest it is easier for one to notice how honest others are, so you kind of get the same level of honesty in return via social eye.
If you are both honest and at least sometimes outspoken, not too polite. Then you can stop dangers before they happen, just by telling "I do not believe that." and not going along in dangerous things. While liars often don't have such emergency stop possibility in their relationships because they are afraid of others pseaking the truth about themselves.
If you are yourself worth some quite high position, you get it easily via honesty, but if you would lie, you wouldn't get it.
In groups honesty makes the group work well together, as things get treated accordingly what they are like and reactions are with wisdom and common sense with the whole group working well together. But that demands goodwill and freedom. Honesty gives room for deserved freedom and freedom to good spirit and that to good will.
If you are somewhat honest, you get somewhat the benefits of honesty. If you lie and act a lot, continually, you get into a mess where people use harsh measures and rotten things get impossible to cure, where people find room only via more harsh ways - so as to reach realism and real power balance, which were in a sense the central point in arranging things when people were honest and sincere and there was goodwill around.