FAQ: Why are Jamtis addresses so long, with nearly 200 characters?
Seraphis and Jamtis solve some long-standing problems of the CryptoNote technology at the base of current Monero, and bring improvements regarding several issues.
One of the prices to pay for achieving this: A need for more information in public addresses, with a corresponding increase in their length.
Jamtis addresses contain 3 keys instead of only 2 like CryptoNote addresses, and the so-called address indexes to support multiple addresses per wallet (now called subaddresses) are much wider.
A different way to convert binary information into easy-to-handle text for addresses called Base32 also makes the addresses about 15% longer overall compared with the current Base58 system. Finally, longer addresses need a bit longer checksums to offer a comparable level of security against errors.
This is a story with many aspects, and I have written a quite long text about a number of them.