While the logical thing would be to place a much higher value on a carded figure compared to a loose example (especially with prices of loose figures creeping up)..it's not always that easy.
For starters, carded figures and loose figures have very different audiences and I would argue that there are far more people out there looking for a loose Imperial Gunner in mint condition with original gun than there are people looking for a sealed Trilogo version.
The only reason original guns and accessories are so valuable these days is simply because so many were lost over the years..(or hoarded up by variant collectors!) but carded figures can't really lose their accessories and are just part and parcel of the figure. Loose figures also "fit" every loose collection, whereas Trilogos do not fit every carded collection..
So while they are still "valuable", the price of a blaster doesn't (or shouldn't) come into the equation when you buy a carded figure, especially if it's going to remain sealed.
In an ideal world, carded figures should be priced based on how common/uncommon they are and also the condition they are in. It's never really been a "thing" to factor the weapons/accessories into the price of a carded figure unless it's something super in demand/crazy rare like those metallic Euro/PBP blasters.
In the recent price guide I attempted I had him down for £80-120 (so you did ok Simon

) based on the figure being around a C8. The one above is a nice figure but it's obviously got an off center bubble which has yellowed and it also has the usual dents. To most carded collectors it's probably a C7/C7+.
If I were valuing this particular figure as a carded collector (which for the most part, I am) based on the rarity of a sealed one & the condition it's in..then I might say £80-100.
If I were valuing this figure as a loose collector based on the prices of loose figures at the moment then I might say more..but then, why would a loose collector be interested unless they were going to open it? :lol:
It's pretty rare for a carded figure to cost less than a loose version but it's not unheard of. The unfortunate downside there however is that it tempts more collectors into opening figures! Lost a lot of Ewoks & Droids figures over the years due to that issue..