Somehow, the OP's actual question about pivoted tonearms with straight vs curved arm tubes (or "wands") got completely lost as the discussion turned to turntable and speaker mass. But most of the main points were made.
(1) As others mentioned, if the arm tube is straight on a conventional pivoted tonearm, then the headshell offset angle must be incorporated into the headshell mount itself. As a consequence, many such tonearms bear headshells that are permanently mounted. This was a trend in design meant to maximize ridgidity from pivot to cartridge. A curved arm wand (J or S) will generally have a higher effective mass than a straight one of equal effective length, simply because the linear length of tubing will be greater compared to the straight version. A curved arm wand will more easily accommodate interchangeable headshells of many different types and weights, because the offset angle does not have to be incorporated into the headshell mount. There are all sorts of ideas and hypotheses about which is better, straight vs J or S-shaped, some of them having to do with resonance and some having to do with weight distribution across the S or J shape and whether one should compensate for that.
(2) Someone mentioned "very short" tonearms, like the Viv. The Viv (and the RS Labs RS-A1 tonearm, which preceded it) is an entirely different animal. Conventional pivoted tonearms have a headshell offset at an angle solely in order to achieve two points of tangency of the cantilever to the groove across the playing surface of the LP, using any of several standard geometries (Baerwald, Lofgren, Stevenson, etc). The Viv and the RS-A1 have no headshell offset angle. Thus they can achieve only one point on the surface of an LP where the cantilever will be tangent to the groove, and generally the tracking angle error is greater for the Viv and RS-A1 than for conventional tonearms, at any other point on the LP. The trade-off is in skating force. The Viv and the RS-A1 will still generate a skating force (except for that one point where there is tangency to the groove, where skating force = 0), but the skating force is not affected by headshell offset angle, since there is none. Conventional tonearms NEVER are free of skating force, because even at those TWO points where the cantilever is tangent to the groove, there is still a skating force due to the headshell offset angle. From my personal experience with the RS-A1, "straight: tonearms (meaning those with no headshell offset) can sound really good, better than you would expect given the much larger tracking angle error of this type of tonearm.