Coinomi supports all Bitcoin forks, but BTCH is not there.
BTCH is a merge fork of 3 separate assets into a Komodo ~250MB asset chain, it is cutting edge stuff, it will take a while for exchanges to work out how to list it, we need to be patient, exchanges are all overwhelmed now, they go for the low hanging fruit first i.e the easy forks
afaik the best way to access BTCH is via BarterDEX (that's how I got my bitcoin gold), from there you can send to exchanges when they're ready.
BTCH is clearly the most advanced fork to date, give it time.
Adding coin to Coinomi , Jaxx, Exodus and such widely used mobile multi-coin wallets will help generate awareness of Hush and BTCH existense among users of the wallets.
I know most of us, in the hush community, have found their way through agama and the online Hush wallet.
But listing on other wallets will be kind of marketing to others.
Below is copied from Coinomi reply on adding electroneum to their wallet:
" We do accept requests from a coin's community, and it helps us gauge the interest a certain coin is generating. But /u/camobit is correct, it is essential that we have a direct contact with the developers of the coin. In the case of Electroneum, being a Monero fork, it will be much easier to integrate once we have added XMR into our app."
Hush can easily be added to coinomi - if the devs contact Coinomi - since Hush is a fork of zcash which is already listed in coinomi