Not un-useful, but the number of Tixati users is already limited on the open internet (and heavily slanted towards certain unsavoury interests). Finding other Tixati users on i2p just limits your potential peer group further.
To be fair Tixati is a bittorrent client using the same standard bittorrent protocol that other clients use. So it will connect to bittorrent swarms, peers, trackers, etc. just like any other I2P bittorrent client. So Tixati users will connect to I2P bittorrent peers using I2PSnark, XD, qBittorrent, and BiglyBT. (and any others I missed)
The big limitation is that there are less bittorrent peers on the I2P network vs the clearnet internet… it’s a big difference. It’ll probably stay that way until there’s more people keeping torrents active within I2P, hopefully in the future.
Other minor limitation is that I2PSnark (& and maybe Tixati) are the only bittorrent clients that can use the bittorrent DHT within I2P, all the other bittorrent clients can only find peers using bittorrent trackers. It’s not a big deal as long as people remember to add I2P trackers to their torrents but it does make things less decentralized. Tixati does claim I2P DHT support but I’m not sure how well it works in practice.