There is another angle: what if you want to express yourself, but, say, Unity is too limiting? Existing game engines were made to express existing ideas and while there is some stretch they do have hard limits.
Hard agree. AFAIK Jon Blow's Braid couldn't be made with an existing engine (at the time) due to its time warping mechanics.
That's a big reason I like developing games with frameworks. It allows reusibility and access to clever code, while still remaining flexible enough to support weird mechanics.
That's a big reason I like developing games with frameworks. It allows reusibility and access to clever code, while still remaining flexible enough to support weird mechanics.