you might need one once you’ve reach an intermediate/advance level. i don’t think getting one before would be neccessarity, a normal dictionary is enough (i still use imiwa most of the time) plus it’s pretty pricey..
i find mine useful when i don’t understand the english translation, and i need it in my native language, but other than that i don’t think it’s that much of a neccessity (especially now with apps and all..) i had to get one for school so that’s why i bought it haha - it depends on what you need it for, it’s quite handy if you’re doing a lot of translation or need to find a kanji you can’t read~ also depending on the model you buy there will be differents dictionaries installed (mine has a dictionary of classical japanese - useful if you’re studying kanbun)