As a former runner I appreciate trails of all kinds. It's easier on your legs and trails are a good way to get around without having to be in traffic. With that being said, the idea that we should be reserving our right of ways for trails alone instead of trails and transit seems shortsighted. While I applaud the rails to trails folks for what they've been doing, the creation of a trail while the use for rails waits for a project only encourages a permanent trail.
In the case of Whittier, the construction of a trail has likely built up political will and precluded the ROW from ever being used for transit ever again which is a real shame since it would be possible to share. It's also possible that it won't be the best alternative. Eventually though it might come in handy. The trail is on the far right alternative within the city of Whittier.
On a similar note, short term gains should not outweigh long term benefits. In the case of Buffalo, the transit authority is looking to sell some ROW that could be used for long term gain. I understand there are trying times around the country, but these types of decisions that aren't looking at the long term consequences are trouble and it points to the loss of long term thinking in how we make decisions.