Earlier quoted context omitted.
That's because 'e' also usually makes previous consonant softer(not in your example though, because it's a loan word I guess), so you'd have to put 'ь' everywhere then.
usually makes - so why not use 'e' only in the cases when it actually does? I don't say 'э' should always be used in place of 'е'. I mean why not use 'э' when it sounds 'э' (without the preceding letter softening) and 'е' when it really sounds 'е'? The Russian writing system tries to be phonetic but doesn't seem to do well this way.
As the sibling comment says, it doesn’t, at least not anymore. It is to a large extent traditional. The current Russian writing system is essentially the same as it was in the early 18th century, when it determinedly deviated from the Church Slavonic. There was a spelling reform right after the Bolshevik revolution in the early 20th century, but it was not particularly significant — they just abolished a couple of letters and forbade the use of a particular letter in the end of words. Since the 18th century, the Russian pronunciation has of course evolved (and anyway, there is no such thing as the Russian pronunciation; there are always dialects). Which, inevitably, has led to deviations between the spelling system and whatever was the standard pronunciation at the time.