taking a 2 week cycle of anything pre contest, and nothing else, is foolish. If that's literally all a person is taking, they should just compete natty, as the results they'll get will be so minimal, if any at all.
Ok, so test shuts down your test production, but it replaces your natural production with synthetic test. Very different from taking a different compound that doesn't do this. That's why a test base is such a big deal.
The biggest issue, in my opinion, with an oral only cycle isn't this, though. It's that the results one is likely to get from an oral only cycle are so minimal that by the time one goes through pct/recovery, no gains will be kept. It's basically a wasted cycle. I COULD see someone doing, say, a dbol only cycle for 6 weeks leading up to a powerlifting competition, or something similar. Or if someone just wanted to look more muscular for a short period of time. If long term results are desirable, oral only cycles are useless.