Wolf who said it has to be bought purely for lkavod shabbos? Food for example as much as it is bought lkavod shabbos, you are still getting your own pleasure.
That’s a very good question. However, it could be argued that (a) food is required for Shabbos, flowers are not; (b) for all practical purposes, one cannot eat without having pleasure from it or, conversely, the purpose of eating food on Shabbos *is* to have pleasure from it — and since it will be done on Shabbos, that makes it for Shabbos. Flowers, when bought with other purposes in mind, does not meet that criteria.
The Wolf