There are manufacturers who make quieter fans now, but they still recommend installing in halls outside bedrooms, presumably due to noise. They are obviously only effective if outside temps drop significantly in the evening.

There are problems with excess dust and other matter being drawn into the house.

If your loft is well insulated, it won’t be the cause of all the heat build up in your home. Overhangs, well positioned trees, awnings, window glass treatment can all help. Simple house fans circulate air and offer cost effective relief.