Hi,
SEF is available by default in Joomla. And HikaShop is compatible with the SEF system in Joomla. You don't need any third party component to have SEF with Joomla and HikaShop.
Also, AceSEF is also compatible with HikaShop, not only Sh404SEF.
JoomSEF states on there website:
support for sef_ext.php files written for OpenSEF or SEF Advance (since v1.4.0)
support for Joomla API router.php files
That's good news for you since HikaShop has both a router.php and a sef_ext.php file for SEF support so you should be able to use it with HikaShop.
HikaShop is an ecommerce extension, not a SEF engine extension. It's not our role to handle all the SEF of your website so you will never see a SEF engine in HikaShop. If we were to do a SEF extension one day, it would be a separate extension, but we don't have any such plan and there is still a lot of things left to do in HikaShop