Where the claim came from
The comparison used a very expensive kind of conventional roof as the baseline, the sort of slate or high-end tile that few houses in the inland valley have. Against that baseline, a per-square-foot price for glass tiles looks competitive. Against a composition shingle roof, which is what most people here are replacing, it is several times the cost.
Pick the baseline you actually have, not the one that makes the headline work.
Active tiles versus the rest
Only a portion of the roof generates electricity. The rest is glass tile that costs more than shingle, more than concrete tile, and does nothing except match. On a house with a big north slope or lots of shade, you are paying premium money for a large area of decorative roofing.
That ratio is the single biggest driver of the final figure and it is buried in the fine print.
Comparing against panels
The fair comparison is a conventional re-roof plus rack-mounted panels sized to the same output. Rack-mounted panels are cheaper per watt, can be angled for better production, and can be removed and reinstalled by any solar company. The glass tile system trades all that for looks.
Looks are worth something, but they should be bought knowingly.
What a roofer sees
Any roof system is only as good as its flashings and underlayment. Glass tiles do not change that. The house still has chimneys, vents and valleys, and those are still where it will leak if they are done badly. A premium surface on ordinary flashing work is still an ordinary roof.
Ask who does the flashing and who answers when it leaks.
The honest position
If you want a solar roof that looks like a roof and you have the budget, it is a legitimate product. If you read that it was cheaper than a normal roof and got excited, slow down and run the numbers on your own house with your own baseline.
I am happy to inspect and give you the conventional side of the comparison to hold against the quote.
What to ask any solar roofing salesperson
Ask for the active-tile percentage on your specific roof, the total installed figure including old roof removal and any deck repairs, the warranty terms on the underlayment and flashings separately from the tiles, and who does the repair if it leaks in year five. If any of those gets a vague answer, the comparison is not finished.