Interface language
HelloGrowthCRM is English-first, and in Thailand that deserves an honest test rather than a shrug. Thai text stores and searches normally, but menus and settings are English. Since the free plan costs nothing, use it to find out whether your least English-comfortable staff will adopt it, because their behaviour decides whether the data is complete.
How growth is priced
Check the upgrade path early: whether the price is published, whether seats can be added individually, and whether your pipeline carries across without a rebuild. Because billing is in dollars while your revenue is in baht, confirm who holds the card and what an annual term commits you to before the decision arrives in a busy month.
Invoicing and payment
Tax invoices belong in the accounting system that issues documents in Thai and meets your filing obligations. The CRM holds the quotation, the approval and the chase, and records the agreed payment method and date, whether that is bank transfer or an instant payment. Keeping the two separate avoids expecting a sales tool to run your finance function.