IMO its a matter of having the correct tools.... a lot of guys don't do enough AN line flaring to recover the expense of the 37° flaring tool.
Don't forget that the flared aluminum line also needs a tube sleeve to go along with that tube nut.
I have used the compression fitting type hard line to AN adapters several times without a problem. Compression fitting on one end and AN male on the other was the type I used....you can get them with AN female also.
I don't remember if they were Earls or Russell.