I'm assuming you have not spent a lot of time trying to prove stuff about non trivial programs if the trade offs between SMT based approaches and interactive theorem provers are not clear to you.

SMT solvers are highly automated, but very opaque and hard to debug. Interactive theorem provers can scale to larger problems and harder properties at the cost of increased manual proof burden. The ever increasing ability of llms to write proofs in a theorem prover has in recent years tipped the balance significantly towards preferring itp based approaches over pure SMT ones. The current state of the art for program verification is probably a mix of llm and traditional (tactics, SMT, etc.) proof automation inside an itp.

ATPs go quite a bit beyond what a SMT solver can do, however you're not stuck with just using ATPs when they are supported. You can still allow for proofs to be manually written with an ATP doesn't work, and in fact SPARK allows for this with Rocq.

Most of what I have to prove is floating-point code where a manual proof is too much of a headache to ever attempt though.