Instant coffee begins with brewed coffee that is processed into a soluble form. Adding water recreates a drink without grinding beans or separating spent grounds at the point of use. That makes its preparation fundamentally different from making a fresh extraction at home.
Its practical value is clear when equipment, time or cleanup space is limited. The source presents it mainly as a compromise, but preferences and products vary, so an old general verdict should not decide every current purchase. Compare the actual product rather than the category's reputation.
Use the manufacturer's starting quantity and then adjust the coffee-to-water ratio to your cup. Check whether the package contains only soluble coffee or also sugar, creamer or flavoring. For travel, portion size and a package that closes well may matter as much as a tasting description. The useful question is whether the resulting drink fits the occasion you are buying it for.
The conversation
A good question can make a better brew.