Why can -04:00 not replace America/New_York in a recurring schedule?

Why can -04:00 not replace America/New_York in a recurring schedule?

1. The offset describes one UTC relationship, while the zone supplies date-dependent regional rules.
2. Numeric offsets can represent only times before the Unix epoch.
3. An IANA zone always has a constant offset but a friendlier name.
4. RFC 3339 forbids numeric offsets on resolved instants.