Disclaimer: This article is fact-summarized as sources indicated and opinion-added by me. I'm open to any further discuss.
Summary: Post-Covid19-Changes may be temporary but as well irreversible. What matters most is the shift from:
Convenience to Safety, Cost to Simple Availablility, Wants to Basic Needs
1. Vietnam's Economic Resilience amid Covid-19
Although GDP 2020 has reduced from 7% to 4.8%, VN is still expected as one of the fastest-growing economies in APAC region with nearly 17 million middle-class household (2030).
2. Consumers' Behavioral Changes
a. Stay home, stay safe
Dining out has been replaced by takeaways & eating at home. "On-th-go lifestyle" replaced to "Safe in-house consumption". This leads to rapid surge in these product categories:
- Health & Nutrition: Milk powder, Yogurt, Functional Foods (Imported, Hand-luggage)
- Cooking aids/Kitchenwares
- Personal Hygiene: Bodywash, Mouthwash, Facial Tissues
- Household Cleaning
b. Broad-based shift to e-commerce
Prior to Covid-19:
98% of sales from physical store while 2% from e-commerce. 
Top sales categories online: Electronic & Media, Fashion.
Post Covid-19:
Footfall to supermarket, grocery stores & wet market reduced.
Upcoming top sales categories: Food, Personal Care.
Challenges: Fulfillment Center & Delivery
3. Omni Channel Basics
Seamless customer experience throughout multi-channels. 
3 key features: (==> Any other features?)
a. Click & Collect
- Make purchase online - Collect at preferred stores/location
- Best for: Time-sensitive promotion
b. Click & Delivery
- Order online - Merchandised delivered to home - Paid via online credit card or COD
c. Reserve & Collect
- Reserve online - Collect & Pay in-store
- Best for: Time-sensitive promotion but still wish to inspecting more suitable products
==> Inventory Mangement for OmniChannel? How?
Sources: