It doesn't, really. AFAIK, there isn't any (or there's limited) laptops with 1070TI's in them. Performance-wise, it's in the same general ballpark as a MaxQ 1080.
In desktops, a 1070TI falls between a 1070 and 1080. Overclocked, it'll rival a stock 1080, but a 1080 can be overclocked itself, opening the gap back up.
It's a solid card and, depending on price may or may not make sense over a 1080.