Why are customer service and its related strategy so important for companies operating global supply ...

From a customer service perspective, global markets and strategy have four important characteristics. First, companies attempt to standardize to reduce complexity, but they have to recognize that global markets need some customization. For example, in contrast to the U.S. market where large retail stores buy in volume quantities for delivery to their large warehouses, less developed countries may have tiny retail stores that are only 80 to 100 square feet. This means deliveries of small quantities, more frequent deliveries, different packaging, etc. Customer service levels have to be adjusted for these markets in terms of delivery schedules, volumes, order fulfillment, and other areas.
Second, global competition often reduces the product life cycle, as previously mentioned, since products can be copied or reengineered quickly by competitors. Technology companies are faced with this phenomenon even in the U.S. market, but globally other products are faced with similar experiences. Technology companies counteract with continual upgrades and new products. Apple, for example, had great success with its iPod, but it quickly followed this with the iPhone, and now the iPad, to maintain financial momentum. Shorter product life cycles present challenges for inventory management with respect to obsolete items. Customer service levels are also impacted because changes have to be made as the product matures in terms of sales volume and then declines, which reduces product profitability. Usually, companies cannot afford to provide the same level of customer service when the product volume declines.
Third, traditional organizational structures and related business models frequently change since companies get more involved in outsourced manufacturing and some logistical activities such as transportation, warehousing, and order fulfillment. All of this impacts the supply chain and its related customer service activities. The collaboration indicated requires effective coordination among the various parties to ensure that customer service levels (on-time delivery, complete orders, reliability, etc.) are maintained.
There are many challenges for supply chain managers. The soft side of global supply chain management presents significant challenges. The social and cultural elements come into play when dealing with foreign business partners and require daily effort to ensure smooth supply chain execution. This is because soft issues and physical problems are, in many cases, not mutually exclusive. Misunderstanding the culture and miscommunicating can cause havoc on the physical side of global supply chain planning and execution. Cross-cultural communication is made complicated by not only different languages and time zones, but also other culturally-rooted practices such as communication styles, different approaches to completing tasks, different attitudes toward conflict, and different decision-making styles, among other factors.
Fourth, globalization introduces more volatility and complexity. It is much more likely that global supply chains will experience challenges with weather, terrorism, strikes, and other disruptions. The need for flexibility and responsiveness is a requisite for customer service throughout the supply chain. The expanded networks cover long distances and many are complex. Trade policy, regulations, tariffs and currency exchange rates exacerbate the level of complexity for global supply chains. Furthermore, the number of intermediaries that can be involved adds another additional layer of complexity.
When considering which is more important, customer service or lowered cost, one must take into consideration not only physical, but soft, cultural factors as well. Some, more affluent sectors may be willing to pay an increased price for goods so long as those goods are backed by a good and robust customer service tail  think customer loyalty. However, more developing nations and counties, whose population may be more defined by fickle youth and rapid change of taste, customer service becomes less important when compared to price point. These phenomenon must then be weighed against the physical cost of providing either prime customer service, competitive cost, or a delicate balancing of both.