p.s. The number of instances in the database is still quite small (you can find out yourself by messaging the bot with the word "stats").
The more instances are added, the better the database becomes.
The idea is to provide a resource that new people can use to find a suitable instance.
By the way, you can use direct messages to communicate with the bot if you don't want to fill your timeline with instance searches.
mastodon.at is a microblogging site that federates with most instances on the Fediverse.