I have Wise for about 5 years and have often made USD to USD transfers to both US based accounts and MXN accounts held in USD (many MXN businesses prefer USD). Ive also made transfers to UK and EU countries, but mostly MXN. That said, I do
recall not being able to make some sort of USD transaction a couple years ago, but for the life of me, can't
recall where or why.
I too bank with Schwab and have for years. I do have an investment portfolio with them but can offer no guidance on whether they require one before allowing the other. They waive ATM
fees including international ATM which was thr original draw, though I see Chase now has similar, at least for whatever type of account I hold with Chase. I can tell you that disputing a credit card charge with Schwab is futile so I still recommend AmEx if you need any buyer protection. Their car rental
insurance was tops when I last compared a couple years ago when I was
renting cars almost weekly in both US (business) and
Mexico (pleasure).
Finally, I had never heard of the Schwab/BoA connection so I googled. Appears BoA purchased Schwab in 1983 but Schwab purchased themselves back in 1987. In 2007, Schwab
sold a small division to BoA. I could find no other connection. Scwab does have affiliates for some services such as actual credit card (vs Visa branded ATM) which may be a concern since you have zero clout with the affiliate CC company.
All I can tell you is Wise has thus far worked well for me. I probably have over 50 transactions with them to a couple dozen recipients in 4 or 5 different countries. ForEx is decent,
fees are reasonable. Beats the heck out of bank wire transfers even when the transfer has no fees (ForEx from banks is notoriously lousy).
Good luck
Peter
PS - I see OP asked about exchange rate on Schwab. I have found their ForEx rates go be pretty decent - very close to "spot market" rates. I have only personally checked MXN (pesos), GBP, snd EUR. The exchange rates via ATM has been more favorable than going to a bank.
BTW- when traveling abroad, I use ATM/cash vs CC almost exclusively due to favorable exchange rate and due to risk of CC theft (unfortunately, fairly common in Mexico).