The "cost" is not less with Wise, it may be or it may not, too close to call.
From HSBC to Thailand you pay a fixed fee of £5 and you get the forex rate when the funds are converted by the BOT, forex is better than the Wise rate. There is a small handling fee by the Thai bank, altogether very little in it and the overall cost using Wise is related to the amount you send. I have only ever cross checked the amounts I send, other amounts may give a different result. At the end of the day it is whatever you think suits best.
I have seen the HSBC card but will stick with Wise, know that suits.