No, if a gift certificate is carefully chosen to suit the person who will receive it and is accompanied by a nice card/letter, it can be much nicer than a gift that may be useless. It’s like in the secular world they have bridal gift registries, where the bride and groom make a list of things they want from a particular store and you pick one of those things and give it to them. You don’t have it here, but if they’re going to get five sets of plates and no sets of silverware then you’re not doing them a great service.
To put it into this situation, if you feel that the point of a gift is just to express esteem and it shouldn’t matter what it is, then fine, but otherwise make the gift something useful.
For instance, at my bat mitzvah, I was given a beautiful necklace by an aunt— something that some people would find gorgeous but that I just didn’t. Another aunt gave me a gift certificate to a jewelry store and I picked out a different necklace that I wear often and think of as my aunt’s gift to me as much as if she had picked it out herself (which b”h she didn’t because she’s a lovely lady and all but we do NOT have the same taste).