What is actually the benefit of Tower vs Bookshelf speakers here? Did you notice any difference? I guess sensitivity slightly higher, more power, maybe slightly better quality given higher price? Always wondered why tower if all below 80hz will be trimmed anyway.
Generally higher sensitivity and greater max SPL are advantages of towers.
Generally cost and low resonances are the advantages of bookshelf speakers.
With towers, you are often paying a premium for the bottom 20-30Hz they add to the sound, but with a sub that is not really relevant.
The bookshelf usually has the same quality drivers and crossover short the low frequency driver.
Obviously there are lots of unique situations, but as a rule of thumb, I would rather have a bookshelf speaker if my budget for two speakers was under ~$1500. This is because that is about the price where manufacturers start getting very serious about adding bracing to prevent cabinet resonance.
Any $500 or less pair of towers I have heard were a mess if you turned up the volume very high because the bass got muddy from cabinet resonance.
As price continues to go up, the tower gets better bracing and is close to a bookshelf for not resonating.
At this point, it generally gets down to cost, looks, and perception. Some people enjoy a little extra bass reinforcement from towers, but it seems to me as more of a EQ flexibility than actually wanting more bass (which turning up your sub would get).
From a value standpoint, unless you need the extra sensitivity or output, the bookshelf is always a better value! For a tower, you are paying a lot for extra handling and shipping costs as well as the larger cabinet. None of that gets better sound quality since you are using a sub for bass.
However, these are gross generalities!
For any given speaker, it is wise to listen and compare the two versions if the opportunity presents itself!