Moot. You can't even select/copy/paste it. Spiders can't crawl it. Users can't resize it so they can read it properly.
No? Then you're using it wrong. sIFR allows each of those features.
Spiders can't crawl it.
sIFR replaces text after the page has loaded. It appears no differently to spiders and search engines.
Users can't resize it so they can read it properly.
A valid concern, but it is likely fix-able. Assuming it hasn't been fixed already. I have no recent experience with this.
That's rubbish. You can't even select flash text + native text in the same selection. It's completely broken.
Also, flash bugs are platform specific. Like printing issues on firefox in linux, z-index issues on some browsers etc etc.
None of this happens with native text.