What is the disadvantage of using a ramp?

I understand that ramps can be a great tool for providing accessibility to buildings and spaces for individuals with disabilities, but I'm curious to know, what are some potential disadvantages of using a ramp? Are there any situations where a ramp might not be the most suitable option, or could there be safety concerns that arise from their use? Additionally, are there any considerations to keep in mind when designing and installing a ramp to ensure its effectiveness and safety for all users?