In the Iran-Iraq war, they used them as ersatz AWACS. Supposedly, they've managed to retrofit I-Hawk SAMs (yes, SAMs) to them, but I have serious problems believing that report, for obvious reasons.
Just because they're buying them, doesn't mean they have a specific mission in mind. Not everyone procures like the US did with the A-10, with a very specific combat situation envisioned. Hell, the US doesn't even do that anymore...look at the friggin' Raptor program.
But anyway...with PGMs, they apparently have a creditable naval strike capability. The Russians designed a variant of the SU-25 for their carrier, at least...
They have them, both purchased outright and ex-Iraqi planes flown to Iran during Desert Storm.