Why Google Map Route API is different from google map?

Question

I request the google route api

{
  "origin":{
    "address": "日本福岡國際機場"
  },
  "destination":{
    "address": "博多車站"
  },
  "travelMode": "TRANSIT",
  "transitPreferences": {
    "allowedTravelModes": ["TRANSIT_TRAVEL_MODE_UNSPECIFIED"],
    "routingPreference": "LESS_WALKING"
  },
  "computeAlternativeRoutes": true,
  "languageCode": "zh-HK",
  "units": "METRIC"
}

even I tried using placeId,

{
  "origin":{
    "placeId": "ChIJrQFpQhaQQTURtx9OWEZ_5hY"
  },
  "destination":{
    "placeId": "ChIJdbP55seRQTURkIu5RT0r4i4"
  },
  "travelMode": "TRANSIT",
  "transitPreferences": {
    "allowedTravelModes": ["TRANSIT_TRAVEL_MODE_UNSPECIFIED"],
    "routingPreference": "LESS_WALKING"
  },
  "computeAlternativeRoutes": true,
  "languageCode": "zh-HK",
  "units": "METRIC"
}

The result shows that only walk method. but if you go to google map to search, it will have subway method.