The coleus sold under the name ‘Wasabi’ (Plectranthus scutellarioides ‘Wasabi’) is a horticultural variety (cultivar) known for the light-green coloring of its foliage, reminiscent of color of wasabi, a very pungent condiment paste used in Japanese cuisine and derived from the plant Eutrema japonicum. The name in no way indicates the taste of the plant, any more than ‘Chocolate Mint’ coleus, with chocolate-brown leaves edged in green, is supposed to suggest it tastes chocolate … or like mint. These are strictly descriptive names.
Note that coleus plants are not considered to be poisonous to humans, although they contain some slightly toxic compounds, such as coleonol (forskolin), a diterpene, that, on very rare occasions, can cause negative skin irritations in individuals with sensitive skin if they are in contact with the plant’s sap. Those compounds are not concentrated enough for the plant to be poisonous when eaten (remember the saying “the dose makes the poison”).
Coleus, however, does contain essential oils that are toxic to dogs and cats and can cause negative reactions if they eat the plant: vomiting, diarrhea, etc.
The names of cultivars of ornamental plants are generally chosen to make the plant more appealing to gardeners and, when not honorific or purely fanciful, tend to describe the color of the plant or its flower, its perfume, its habit, etc. They almost never have any real link with their taste.
I wouldn’t recommend you chew on the flowers of Vanilla Strawberry hydrangea (Hydrangea paniculata ‘Renhy’) either: I’m sure you’ll find their taste very ordinary!