Big building projects are an extension of the ego of the pastor or church leadership in many cases. The biggest building is assumed to be the most prominent, regardless of how well the needs of congregants are met or the value of the church to the community (through charity or outreach).
I’ve seen churches focus on building while abandoning relief childcare for special needs children, less free childcare for women on job interviews and cutting back mission trips.
This is why we attend a church where we not only teach Dave Ramsey’s FPU course, but they have a “get out of debt” goal to pay off the church’s mortgage before building up a maintenance sinking fund.
Used to attend a megachurch years ago where the pastor asked us to raise 1 million for the new building. Then the next million fundraiser was supposed to be for missions but then another building fundraiser was added instead. I prefer smaller churches now with constrained budget priorities and the emphasis is on the Word and not floating cameras everywhere either.