Those do not accurately reproduce the Safari experience. Many bugs or performance issues will be unique to the way Apple builds and packages webkit, or the spec

Those do not accurately reproduce the Safari experience. Many bugs or performance issues will be unique to the way Apple builds and packages webkit, or the specific graphics stack they use. Back before Windows Safari was killed it honestly was a bad imitation of iOS Safari too - it didn't include the media codecs, etc - but it was better than nothing. Windows Safari still theoretically exists (I was told not too long ago by a little bird that iTunes uses it)