Last few months been paying online, last night I played live, playing 10/20 (= 7.5/15 USD) at my local casino.

In the past I have always opened pre-flop with a 3BB sizing when playing live in this 10/20 game, (standard of players here is a real mix of guys who should be playing 2/5). However last night I decided to open for 2.5BB instead. I felt this had three advantages

1) Its a weird RFI sizing opening for 50 every time, everyone else opens for 60, so I felt like it made everyone else feel uncomfortable and awkward which is seems like a positive for me.
2) If I got 3-bet then it would probably be only to 150, not the usual 180 that happened when everyone else opened to 60, so I only had to call 100 more to a 3-bet not 120 more
3) Made me look like an online player which in general has a fairly decent stereotype for being at least a semi competent image, which is another positive

Anyway, why do we open 3BB live and only 2.5BB or less online? Should we open 2.5BB live? what are the pros and cons of doing this?