Most studio monitors are designed to work in near field. In this placement scenario, direct sound emitted by the speakers reaches the ears much sooner than the reflections from walls, secondary sound emitted by speaker boxes etc. They are also designed to be pointed more or less exactly at listener's ears at head level.
In home listening, speakers are usually placed relatively far from the listener, and reflections have a chance of reaching the ears at approximately same time as directly radiated sound. Also when listening at home, people seldom sit still, with ears exactly aligned with speaker's tweeters. Most listening takes place off-axis from the speaker.
Hi-Fi speaker designers often optimize for off-axis dispersion and try to minimize secondary sound radiation from the speaker boxes and panels. For near field monitor, these parameters are just not on the design brief.
So I’m wondering if the Genelec 8030C would work for far-field off-axis listening, or whether they really only work as desk-top speakers. Note, this has nothing to do with whether they need a sub, rather the issue is whether the design is suitable for non-proximate listening.