Let's talk about the key points first: even if this game is labeled “free”, at its heart it's still about spending money and playing games. The national war in the whole server sounds passionate, but it is actually a crushing show of krypton gold bosses. You have worked hard to accumulate troops, and they can recharge in seconds with just one click. But if you are the kind of ruthless person who can resist not paying a dime and play online games as a stand-alone game, then it is actually a bit interesting - the strategic layout of conquering cities and territories, the combination of troops, and the diplomatic game are at least better than mindless automatic path finding.
What's the most enjoyable thing about a single player? You control the rhythm yourself. You can stop whenever you want, without fear of being kicked by the guild, or getting up in the middle of the night to defend the city. Online games give you the "anxiety of winning", forcing you to stay online, socialize, and top up money. Siege falls right into this gray area: it gives you the skeleton of a real strategy, but drains your time with endless quests and rankings.
If I really want to experience the Three Kingdoms War, I would rather play Total War Three Kingdoms or the Three Kingdoms series, at least without the krypton gold boss paying 999 for a sword. But if you are tired of the loneliness of pure single player and want to find some excitement of "living human confrontation" without spending money on virtual values - then you can try Siege City and play it as a long-term strategy simulator. Remember, zero recharge is the soul of single-player, don't be kidnapped by the rankings.