Where it comes from
Q2 FY3/2026 results briefing Q&A summary (Japanese) Nintendo Co., Ltd. IR · 5 November 2025 Open the original ↗
The line in the source
それが『ポケットモンスター 赤・緑』が生まれた理由の一つでもあります。 In English
That is also one of the reasons Red/Green were born (no mention of trading in this answer)