They can't take as much force and they're less reliable. Sometime in the 90s-ish a new test came into force that greatly increased the impact they had to take without unlatching and continue working. The pull bars made it easier to meet because they're secured on both sides.

The pull-up latches also caused issues for people with long nails. In some places spiders liked to nest inside them. Places with snow had issues with a sheet of ice forming over the entire panel, an issue that also occurs with modern flush latches.