[pavel_lishin]

But ф is absolutely not the sound that "th" makes.

In fact, in Russian, at least, we don't have a "th" sound.

But this is better than using Д in place of "A".

[LfLxfxxLxfxx]

Actually, for most of its existence, Cyrillic has had a θ (theta) like in Greek, used only in loanwords and pronounced either as ф (f) or т (t) because the th sound is not part of Slavic phonetics. θ was dropped fairly recently - in the 20th century.

[tliltocatl]

It absolutely doesn't as pronounced now, yet Thomas is Фома, Theodor is Феодор, etc. Just like Hertz is Герц, even through Г and H are as far from each other as one can get.

[armenarmen]

That h -> г always confused me when “Х” is right there

[tliltocatl]

Х is ch in Bach rather than h, and apparently, anglophones can distinguish those. I can't.

[d_silin]

Yeah, it is just фe most aesфetically pleasing letter for фis case.