What should I understand from "clear for straight in app"?

[peekay4]

Yes there are two major criteria required for a straight-in approach to be published:

1. The final approach course must be within 30 degrees of the runway alignment
2. A "normal" rate of descent can be maintained

(Without waivers the max descent gradient for a straight-in approach is typically 400' per NM or 3.77 degrees).

So for circle-only approaches like the one at LGTS -- where the final course is aligned with a runway -- it's almost "by definition" that a normal 3-degree stabilized approach would not be possible. That's the reason the approach is circle-only.

But Lantirn is correct that an actual circling procedure is not required to be flown in all cases.

E.g., barring other factors it would be legal for a private pilot shooting the same approach on a little Cessna to fly the steep 6-degree descent from the FAF and then land without circling.