I will be quoting from the Burning Wheel Gold rulebook.
Fight for what your character believes. Everything else in the rules tells either how to craft that character's beliefs or how to fight for them. (Foreword by Jake Norwood)
At its core BW is a character oriented game. It is narrative first and rules second but the narrative revolves around the characters and their relationships. If the characters are just there to experience the story without being its source, that's not doing BW as intended.
Burning Wheel's core mechanics, advancement and Artha rules demand more-than-usual attention from the player. Skill or stat advancement isn't an afterthought, but rather a crucial part of the game. The decision to solve a problem with cold steel or silken words isn't just one of better numerical values - it's a question of who you, the player, want your character to become. (Foreword by Jake Norwood)
Burning Wheel is demanding for players. This doesn't necessarily mean BW is for experienced players, it's for invested players. They are expected to know what their characters are capable of and what they want to accomplish. Experienced P&P players don't necessarily do better because BW does some things significantly differently than other games. A fresh player might cope better than an experienced D&D veteran who is accustomed to crunching numbers and skimming supplement books and playing tactical combat.
The GM may veto a character that he feels has been min-maxed. Simply chant these magic words: "I don't think he really fits in with the game or the other characters." (p. 106)
It is the philosophy of the system that some tasks are either too complex to accomplish without help or simply too difficult to accomplish at all. Sometimes, high obstacles will force players to be creative and think of another way around. (p. 15)
The game's basic rules cover combat and non-combat situations in equally detailed manner. The main part of the basic rules is the character advancement. The learning-by-doing of skills, the difficulties, the helping rules and the Artha system are tied together in a very tight knot at the games center.
Beliefs, Instincts and traits (BITs) are the primary conduit between the player, his character and the artha system. Setting out BITs for his character, a player states to the GM and the group what his goals in play are for this character. (p. 61)
All expert rules are there just to have more detailed resolution for certain situations. There are advanced rules for verbal disputes (Duel of Wits) tactical move and shoot archer battle and small group tactics system (Range and Cover) and an extremely detailed melee duel and brawl (Fight). They are very detailed and not meant to be used for every fight or argument.
Vincent's advice ["Roll dice or say 'yes'" by Vincent Baker of Dogs in the Vineyard] is perfect for Burning Wheel. Unless there is something at stake in the story you have created, don't bother with the dice. (p. 72)
Other rules are also only meant to be used only when the beliefs of the characters are at stake. Money and wealth is abstracted in a separate attribute. Travel and other stuff is glossed over unless it's important to the beliefs. Low stakes fights get resolved with a simple ability test.
The rules go equally well with slow political plots and fast action scenarios. However the focus on advancement as the main game engine demands the attention to stay with the same characters for some time to get the game really going.