It's not that it requires them to be tactical, but that it makes it more of a downtime activity; something that requires a little consideration and some minor effort on the players part. It's really not a waste of time if you do it right; it can be as simple as "you pay X amount to learn ALL THE THINGS," or if you want to be more complicated there are ample opportunities to <insert role playing here>.

It also seems like a ridiculous supposition that, while traversing a dangerous area fraught with all sorts of perilous traps and vicious enemies, the party would stop to spend some time staring at an item. They COULD do that, but doing so would pose a risk to them not totally dissimilar to camping in said dangerous area.

It also tends to make players more invested in the item. If you give a player a +1 weapon that they can use immediately with little effort then you've just given them a mechanical upgrade. If you give them a +1 weapon that they then have to spend time learning what it is then they've become invested in that item and it allows for an easy opportunity to drop some fluff on to it as well.

A +1 weapon is kind of a bad example though as I do this mostly with items that have multiple effects or different parts of the same effect. For example; a +1 vs Lycanthropes weapon that's been cursed could be broken down as a <+1><vs Lycanthropes><that has a curse,> each little section representing one cast of the spell, or in the case of 5e I might use the attunement rules.

Mostly I do it because I want my magic items to feel special and magical instead of simply being mechanical bonuses. I have had players carry around a specific magic item, sometimes to their own detriment, just because they really liked it and felt a special bond with it PURELY because they had to actually invest some time into learning about it.