I don’t think there is any reason at all for you to get a 415 instead of a 442. As you said, if you want to play with any modern instruments (or most amateur recorder groups), you’d need the 442. If you were an advanced player and/or knew say some people who play on period instruments at 415, then sure, the 415 would be better, but otherwise I don’t see any good reason.
One negative is that a 415 would be somewhat larger (lower pitch = larger), so if you have trouble with finger stretching even on an alto (as I do), the 415 would be less desirable. One of the things I like best about the Bernolin is the GREAT hole positions for both the left and right hands. Even though the 442 is large by alto standards (heavier by 2 ounces than most plastic Aulos or Yamaha instruments, and fatter too), its hole positions are about the most player friendly.
Hope this helps. You asked this awhile ago, so maybe you have already bought it by now, I suppose.