Why use Paypal Standard at all?

Hi,

They are for two different purposes.
For example, if you use PayPal Express, your website usually don't gather the customer's address before the payment is made since the customer can click on the "express checkout" button before entering his address on your website. The address is actually gathered after the payment when PayPal notifies HikaShop of the payment and the order is created on your website.
Because of that, you don't know where the customer is and thus you don't know which tax should be applicable if any. So unless you configure PayPal to add the taxes, your website won't charge the taxes on the products sold as the law requires.
On our website for example we don't want that and thus we're using the normal PayPal plugin and not the express checkout.
Or suppose you want to add shipping costs when the USPS plugin or the FedEx plugin of HikaShop with the customer able to choose on your checkout. If your customer click on the express checkout button before the checkout and skips your checkout, then that's not possible.
Now if you configure the express checkout plugin to display the button at the end of your checkout, you can do that, but it's not express anymore