Apologies in advance to my US and Canadian dive buddies, but you guys are making your judgments based on a different set of laws and banking regulations than are enforced in Thailand (where Khao Lak is located). Your responses are incorrect.
To answer the OP, YES it is common practice here. Credit card fraud is rampant in SE Asia, and making credit card charges offline (just by using the number supplied by the customer) is very ill-advised. Setting up an internet payment system through a company website is a very involved process that many small companies simply choose not to do. Most of us can accept credit cards on-site (where we swipe the physical card through the machine and perform an on-line charge). Naturally, if you are there and the machine is in Thailand, this isn't an option.
PayPal is also not generally an option here because of PayPal's requirements that a recipient have a credit card against which PayPal checks the validity of the account. "Juridic persons" (businesses) here are not permitted by Thai banking laws to have credit card accounts, so that in order to receive a PayPal transfer, a company would have to ask the customer to send the money to a "physical person" (a private individual) rather than to the company. The same is true for Western Union. Both of these, in my view, are more "iffy" than sending the money to a bank account in a company name since you are sending the funds to an individual with whom you have no contract at all. If that money disappears, it becomes much more difficult for you to make a claim as the person you send the money to may not be a Director of the company at all. The most common practice here is to ask for a wire transfer, sent to an account in the name of the company that runs the operation. In order to set up a commercial account here, companies have to provide the banks with all of the company registration documents, tax information, etc.
In sum, it's perfectly safe for you to issue a wire transfer order to the company to pay for your dive trip!