Yes, this should not become a self-promotion tool, but a way for users to express their preferences and let others know where they can be found for different activities. Worst case scenario is that apps show a pop-up right when you log in and try to trick you into recommending them. Your app manager is a great place to offer these best practices to developers. For example, when a developer creates their first app, they could be presented with options on integrating recommendation features in just the right places.
Nosta now shows app recommendations on profiles (NIP-89). They look like this:

Click one and you see details, like this:

This new feature should be great for discovering new clients and more easily connecting with others in the places they are active in.
You can create recommendations via nostr:npub1xdtducdnjerex88gkg2qk2atsdlqsyxqaag4h05jmcpyspqt30wscmntxy's fantastic App Manager here: https://nostrapp.link/
Check his profile to see which apps he recommends: https://nosta.me/nprofile1qqsrx4k7vxeev3unrn5ty9qt9w4cxlsgzrqw752mh6fduqjgqs9chhgpz4mhxue69uhhyetvv9ujuerpd46hxtnfduhs8e2cla
This feature will be integrated in a few smaller ways into Nosta in the future. For example, when recommending apps during profile setup. Or linking out directly to the apps a user recommends from their profile.
Nosta is now listed in the Nostr App Manager. This is a new system for recommending apps. Adding apps to your profile helps others find out in which parts of the ecosystem you are active - great for discovery. Nosta profiles will also soon show your app recommendations.
See the Nosta app listing here:
Profile editing on Nosta works now. Some refinements are still to come, like addressing both "name" and "display name", better validation, and tips for potentially confusing fields. Another important feature is indicating when there multiple profile versions were found on relays, letting you pick which one you want to use moving forward, and then updating all relays accordingly. There's always more to do, but the basics should be there now. If you try it, please share your feedback.

The icon for handles (NIP-05) was changed. It was a check, indicating that some type of account verification had happened. That's not accurate though. Handles are just human-readable shortcuts, often provided by third-party providers, without any sort of identification process. The new icon is more general and avoids that association. Based on this conversation on Stacker News: https://stacker.news/items/173439

Nosta profiles now show stalls and products (NIP-15). For example: https://nosta.me/27c3d086c54a1862d38bf4f0ffb7c4f1be21a037b8ce3a964b8ed34bb340914f
You can now see files (NIP-94) on Nosta profiles. Just basic support for now, showing images. We'll keep iterating on this. Here's an example: https://nosta.me/verbiricha@snort.social
We have a simple app directory to encourage users to explore all Nostr has to offer. How can this be improved? What apps should be added? https://nosta.me/directory
The site received an update today. You now get a nice summary of all profile activity right away, instead of having to click through many (potentially empty) tabs. Also added are received zaps. Heads up, lots of details are still a work-in-progress. Here's an example: https://nosta.me/nprofile1qqsph3c2q9yt8uckmgelu0yf7glruudvfluesqn7cuftjpwdynm2gygpz3mhxue69uhhyetvv9ujuerpd46hxtnfducms3fc?t=black