Horses for courses relly. I think the panels are all standard sizes now as well? When done tastefully, they almost seamlessly blend with the tile (limits tile choices), certainly from a distance. Some new builds near me, you can’t really see the panels until up close. Raised panels do have an issue in that birds/rodents/etc. nest below them and can cause major damage if unchecked. This is why pest protection (unsightly up close) is a must. The major cost of dealing with nesting under panels comes from the labour and probable need for scaffolding etc. to resolve - i.e. minimum of £2k.

More importantly solar works more efficiently when the panels are cooler. There is a reason most installs have a chunky air gap underneath.

That and op said it's more expensive. Why would you do it flush, then? Looks? Eh, I prefer practicality over form and many architects would agree with being more honest.