I can’t speak for all applications, but in the case of HD Admin donations have been an essential source of income. It’s enabled me to work full time on it and other open-source works, and bring on board additional developers to greatly help with development.
This ultimately means better features for our users, many of which drive their gameplay and provide a great source of revenue for them. For instance, since 2019, HD Admin directly has earned developers over 350 million Robux. It has also driven millions of views on YouTube, which consequently provide game developers and their games with greater exposure.
In terms of teleportation, this does have quite a niche legitimate use, however we still find many groups (such as war clans) utilising it to move their members between other group games (such as an apposing clans fort).
Once solution is to introduce an ability for developers to whitelist desired applications.